* fixed bchannel cleaning race condition with new bchannel state (CLEAN_REQUEST)

* fixed bchannel cleaning race condition with new bchannel state (CLEAN_REQUEST)
* added early bridge-hook, so we know if we need to generate ringing or
  can take it from the far end chan_misdn channel (if available)
* fixed the issue, that we may not activate the bchannel on PTMP,
  when we receive ALERTING/PROCEEDING/PROGRESS, only on CONNECT. There might
  be other PTMP devices and we might disturb their bchannel.

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@34552 65c4cc65-6c06-0410-ace0-fbb531ad65f3