leap_mx is started twice on deploy

looking at the log in #6687 (closed), leap_mx is started an quickly restarted afterwards, most probably during the initial deploy run:

root@node1:~# cat /var/log/leap_mx.log 
2015-01-29 21:10:55+0000 [-] Log opened.
2015-01-29 21:10:55+0000 [-] twistd 13.2.0 (/usr/bin/python 2.7.3) starting up.
2015-01-29 21:10:55+0000 [-] reactor class: twisted.internet.epollreactor.EPollReactor.
2015-01-29 21:10:55+0000 [-] AliasResolverFactory starting on 4242
2015-01-29 21:10:55+0000 [-] Starting factory 
2015-01-29 21:10:55+0000 [-] CheckRecipientAccessFactory starting on 2244
2015-01-29 21:10:55+0000 [-] Starting factory 
2015-01-29 21:10:55+0000 [-] Watching '/var/mail/vmail/Maildir' --- Recursive: True
2015-01-29 21:10:56+0000 [-] Received SIGTERM, shutting down.
2015-01-29 21:10:56+0000 [-] (TCP Port 2244 Closed)
2015-01-29 21:10:56+0000 [-] Stopping factory 
2015-01-29 21:10:56+0000 [-] (TCP Port 4242 Closed)
2015-01-29 21:10:56+0000 [-] Stopping factory 
2015-01-29 21:10:56+0000 [-] Main loop terminated.
2015-01-29 21:10:56+0000 [-] Server Shut Down.
2015-01-29 21:10:56+0000 [-] Log opened.
2015-01-29 21:10:56+0000 [-] twistd 13.2.0 (/usr/bin/python 2.7.3) starting up.
2015-01-29 21:10:56+0000 [-] reactor class: twisted.internet.epollreactor.EPollReactor.
2015-01-29 21:10:56+0000 [-] AliasResolverFactory starting on 4242
2015-01-29 21:10:56+0000 [-] Starting factory 
2015-01-29 21:10:56+0000 [-] CheckRecipientAccessFactory starting on 2244
2015-01-29 21:10:56+0000 [-] Starting factory 
2015-01-29 21:10:56+0000 [-] Watching '/var/mail/vmail/Maildir' --- Recursive: True

(from redmine: created on 2015-02-05, closed on 2015-04-14, relates #6687 (closed))