Merged revisions 167620 via svnmerge from

Merged revisions 167620 via svnmerge from
https://origsvn.digium.com/svn/asterisk/branches/1.4

........
  r167620 | kpfleming | 2009-01-07 17:32:21 -0600 (Wed, 07 Jan 2009) | 5 lines

  When a SIP request or response arrives for a dialog with an associated Asterisk channel, and the lock on that channel cannot be obtained because it is held by another thread, instead of dropping the request/response, queue it for later processing when the channel lock becomes available.

  http://reviewboard.digium.com/r/123/
........

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@167700 65c4cc65-6c06-0410-ace0-fbb531ad65f3