[FIX] changing accounts on the fly was not working

Fixed a regression that was introduced with commit
36b49c5de05d51517f2c75225d439bdef2bc7bda 

This commit prevents the configuration of the connection settings while
a connection is established and so it was not possible anymore to just
switch connections without disconnecting first.

Change-Id: Icdea136b79dd39ca9aed72c579f6ade86ae774d4
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1300
Tested-by: Jenkins CI
Reviewed-by: Stefan Rossbach <srossbach@arcor.de>