stop adding 'username@' to incoming IAX2 channel names, so that they can be...

stop adding 'username@' to incoming IAX2 channel names, so that they can be properly matched in the device-state system (issue #5081)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@6477 65c4cc65-6c06-0410-ace0-fbb531ad65f3