soledad.client: support python 2.6

that's what's shipped in osx 10.7, that we were supporting until not long ago.

2014-02-28 02:07:55,721 - DEBUG    - L#53   : leap:write() - 	  File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/threading.py", line 504, in __bootstrap
2014-02-28 02:07:55,722 - DEBUG    - L#53   : leap:write() - 	    self.__bootstrap_inner()
2014-02-28 02:07:55,722 - DEBUG    - L#53   : leap:write() - 	  File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/threading.py", line 532, in __bootstrap_inner
2014-02-28 02:07:55,722 - DEBUG    - L#53   : leap:write() - 	    self.run()
2014-02-28 02:07:55,722 - DEBUG    - L#53   : leap:write() - 	  File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/threading.py", line 484, in run
2014-02-28 02:07:55,722 - DEBUG    - L#53   : leap:write() - 	    self.__target(*self.__args, **self.__kwargs)
2014-02-28 02:07:55,723 - DEBUG    - L#53   : leap:write() - 	---  ---
2014-02-28 02:07:55,723 - DEBUG    - L#53   : leap:write() - 	  File "/Users/kaliy/.Virtualenvs/leap-client/lib/python2.6/site-packages/Twisted-13.0.0-py2.6-macosx-10.7-intel.egg/twisted/python/threadpool.py", line 172, in _worker
2014-02-28 02:07:55,723 - DEBUG    - L#53   : leap:write() - 	    result = context.call(ctx, function, *args, **kwargs)
2014-02-28 02:07:55,723 - DEBUG    - L#53   : leap:write() - 	  File "/Users/kaliy/.Virtualenvs/leap-client/lib/python2.6/site-packages/Twisted-13.0.0-py2.6-macosx-10.7-intel.egg/twisted/python/context.py", line 118, in callWithContext
2014-02-28 02:07:55,724 - DEBUG    - L#53   : leap:write() - 	    return self.currentContext().callWithContext(ctx, func, *args, **kw)
2014-02-28 02:07:55,724 - DEBUG    - L#53   : leap:write() - 	  File "/Users/kaliy/.Virtualenvs/leap-client/lib/python2.6/site-packages/Twisted-13.0.0-py2.6-macosx-10.7-intel.egg/twisted/python/context.py", line 81, in callWithContext
2014-02-28 02:07:55,724 - DEBUG    - L#53   : leap:write() - 	    return func(*args,**kw)
2014-02-28 02:07:55,724 - DEBUG    - L#53   : leap:write() - 	  File "/Users/kaliy/leap/bitmask_client/src/leap/bitmask/services/soledad/soledadbootstrapper.py", line 281, in load_and_sync_soledad
2014-02-28 02:07:55,724 - DEBUG    - L#53   : leap:write() - 	    server_url, cert_file, token)
2014-02-28 02:07:55,725 - DEBUG    - L#53   : leap:write() - 	  File "/Users/kaliy/leap/bitmask_client/src/leap/bitmask/services/soledad/soledadbootstrapper.py", line 395, in _try_soledad_init
2014-02-28 02:07:55,725 - DEBUG    - L#53   : leap:write() - 	    auth_token=auth_token)
2014-02-28 02:07:55,725 - DEBUG    - L#53   : leap:write() - 	  File "/Users/kaliy/leap/soledad/client/src/leap/soledad/client/__init__.py", line 301, in __init__
2014-02-28 02:07:55,725 - DEBUG    - L#53   : leap:write() - 	    self._bootstrap()  # might raise BootstrapSequenceError()
2014-02-28 02:07:55,726 - DEBUG    - L#53   : leap:write() - 	  File "/Users/kaliy/leap/soledad/client/src/leap/soledad/client/__init__.py", line 411, in _bootstrap
2014-02-28 02:07:55,726 - DEBUG    - L#53   : leap:write() - 	    token, timeout = self._shared_db.lock()
2014-02-28 02:07:55,726 - DEBUG    - L#53   : leap:write() - 	  File "/Users/kaliy/leap/soledad/client/src/leap/soledad/client/__init__.py", line 712, in _shared_db
2014-02-28 02:07:55,726 - DEBUG    - L#53   : leap:write() - 	    creds=self._creds)
2014-02-28 02:07:55,726 - DEBUG    - L#53   : leap:write() - 	  File "/Users/kaliy/leap/soledad/client/src/leap/soledad/client/shared_db.py", line 113, in open_database
2014-02-28 02:07:55,727 - DEBUG    - L#53   : leap:write() - 	    db.open(create)
2014-02-28 02:07:55,727 - DEBUG    - L#53   : leap:write() - 	  File "/Users/kaliy/.Virtualenvs/leap-client/lib/python2.6/site-packages/u1db-00.01.04-py2.6.egg/u1db/remote/http_database.py", line 67, in open
2014-02-28 02:07:55,727 - DEBUG    - L#53   : leap:write() - 	    self._check()
2014-02-28 02:07:55,727 - DEBUG    - L#53   : leap:write() - 	  File "/Users/kaliy/.Virtualenvs/leap-client/lib/python2.6/site-packages/u1db-00.01.04-py2.6.egg/u1db/remote/http_database.py", line 70, in _check
2014-02-28 02:07:55,727 - DEBUG    - L#53   : leap:write() - 	    return self._request_json('GET', [])[0]
2014-02-28 02:07:55,728 - DEBUG    - L#53   : leap:write() - 	  File "/Users/kaliy/.Virtualenvs/leap-client/lib/python2.6/site-packages/u1db-00.01.04-py2.6.egg/u1db/remote/http_client.py", line 217, in _request_json
2014-02-28 02:07:55,728 - DEBUG    - L#53   : leap:write() - 	    content_type)
2014-02-28 02:07:55,728 - DEBUG    - L#53   : leap:write() - 	  File "/Users/kaliy/.Virtualenvs/leap-client/lib/python2.6/site-packages/u1db-00.01.04-py2.6.egg/u1db/remote/http_client.py", line 208, in _request
2014-02-28 02:07:55,728 - DEBUG    - L#53   : leap:write() - 	    self._conn.request(method, url_query, body, headers)
2014-02-28 02:07:55,729 - DEBUG    - L#53   : leap:write() - 	  File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/httplib.py", line 914, in request
2014-02-28 02:07:55,729 - DEBUG    - L#53   : leap:write() - 	    self._send_request(method, url, body, headers)
2014-02-28 02:07:55,729 - DEBUG    - L#53   : leap:write() - 	  File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/httplib.py", line 951, in _send_request
2014-02-28 02:07:55,729 - DEBUG    - L#53   : leap:write() - 	    self.endheaders()
2014-02-28 02:07:55,729 - DEBUG    - L#53   : leap:write() - 	  File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/httplib.py", line 908, in endheaders
2014-02-28 02:07:55,730 - DEBUG    - L#53   : leap:write() - 	    self._send_output()
2014-02-28 02:07:55,730 - DEBUG    - L#53   : leap:write() - 	  File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/httplib.py", line 780, in _send_output
2014-02-28 02:07:55,730 - DEBUG    - L#53   : leap:write() - 	    self.send(msg)
2014-02-28 02:07:55,730 - DEBUG    - L#53   : leap:write() - 	  File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/httplib.py", line 739, in send
2014-02-28 02:07:55,730 - DEBUG    - L#53   : leap:write() - 	    self.connect()
2014-02-28 02:07:55,731 - DEBUG    - L#53   : leap:write() - 	  File "/Users/kaliy/leap/soledad/client/src/leap/soledad/client/__init__.py", line 1316, in connect
2014-02-28 02:07:55,731 - DEBUG    - L#53   : leap:write() - 	    SOLEDAD_TIMEOUT, self.source_address)
2014-02-28 02:07:55,731 - DEBUG    - L#53   : leap:write() - 	exceptions.AttributeError: VerifiedHTTPSConnection instance has no attribute 'source_address'

(from redmine: created on 2014-02-27, closed on 2014-03-16)