Ensure after-bridge behavior is correct when moving from Stasis to a non-Stasis bridge.

Ensure after-bridge behavior is correct when moving from Stasis to a non-Stasis bridge.

Because of the departable state of channels that enter Stasis bridges, Stasis has to
take responsibility for directing the channel to its intended after-bridge destination
if the channel moves from a Stasis bridge to a non-Stasis bridge. This change ensures
that when such a move occurs, when the channel leaves the bridging system, any after
bridge gotos are honored.

Review: https://reviewboard.asterisk.org/r/3920

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/12@421792 65c4cc65-6c06-0410-ace0-fbb531ad65f3