Prevent automagic things from happening to Stasis application bridges

This prevents swap optimization, merges, and transfers involving Stasis
application bridges. It wouldn't be nice if the bridge you thought you
owned disappeared from under you.

Reported-by: Richard Mudgett


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@396722 f38db490-d61c-443f-a65b-d21fe96a405b