If the RTP stack is already being operated in callback mode, then suspend it...

If the RTP stack is already being operated in callback mode, then suspend it upon switching to P2P callback bridging. Once P2P callback bridging has ended, then restore callback mode.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@41303 65c4cc65-6c06-0410-ace0-fbb531ad65f3