webapp: alert on 409 responses

They might be meaningful response codes for some scenarios. But
so far we are not conciously sending them out. If they occur that
is because we handed them down from couch. So we might want to
fix the underlying issue. Couch 409s should be caught by the webapp
and handled there.

puppet/modules/site_check_mk/files/agent/logwatch/webapp.cfg

 /var/log/leap/webapp.log
 # check for webapp errors
  C Completed 500
+# also alert conflicts. They might be meaningful response codes
+# but so far we were just handing them on from couch and they
+# indicated some actual problem.
+ C Completed 409
 # couch connection issues
  C webapp.*Could not connect to couch database messages due to 401 Unauthorized: {"error":"unauthorized","reason":"You are not a server admin."}
 # ignore RoutingErrors that rails throw when it can't handle a url