leap-mx package should depend on python-couchdb

root@starfish:~# /etc/init.d/leap-mx status
[FAIL] leap_mx is not running ... failed!
root@starfish:~# /etc/init.d/leap-mx start
Starting leap_mx: twistdUnhandled Error
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/twisted/application/app.py", line 652, in run
    runApp(config)
  File "/usr/lib/python2.7/dist-packages/twisted/scripts/twistd.py", line 23, in runApp
    _SomeApplicationRunner(config).run()
  File "/usr/lib/python2.7/dist-packages/twisted/application/app.py", line 386, in run
    self.application = self.createOrGetApplication()
  File "/usr/lib/python2.7/dist-packages/twisted/application/app.py", line 451, in createOrGetApplication
    application = getApplication(self.config, passphrase)
---  ---
  File "/usr/lib/python2.7/dist-packages/twisted/application/app.py", line 462, in getApplication
    application = service.loadApplication(filename, style, passphrase)
  File "/usr/lib/python2.7/dist-packages/twisted/application/service.py", line 405, in loadApplication
    application = sob.loadValueFromFile(filename, 'application', passphrase)
  File "/usr/lib/python2.7/dist-packages/twisted/persisted/sob.py", line 210, in loadValueFromFile
    exec fileObj in d, d
  File "/usr/share/app/leap_mx.tac", line 24, in 
    from leap.mx.mail_receiver import MailReceiver
  File "/usr/lib/python2.7/dist-packages/leap/mx/mail_receiver.py", line 41, in 
    from leap.soledad.common.couch import CouchDatabase
  File "/usr/lib/python2.7/dist-packages/leap/soledad/common/couch.py", line 32, in 
    from couchdb.client import Server, Document as CouchDocument
exceptions.ImportError: No module named couchdb.client

Failed to load application: No module named couchdb.client

(from redmine: created on 2013-08-29, closed on 2013-08-31)