Merged revisions 320057 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.8

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  r320057 | rmudgett | 2011-05-20 11:43:02 -0500 (Fri, 20 May 2011) | 19 lines
  
  Crash while transferring a call during DTMF feature timeout.
  
  When a call is being attended transferred during the time between
  AST_FRAME_DTMF_BEGIN and AST_FRAME_DTMF_END, the transferred channel
  becomes a zombie (so tech data is not available), making ast_dtmf_stream()
  segfault when it tries to send the DTMF digit (at least with SIP
  channels).
  
  Patch based on feature-end-zombie.patch uploaded by Irontec (license 1256)
  
  * Check for zombies when ast_channel_bridge() returns.
  
  * Guarantee that the fo parameter value is initialized in
  ast_channel_bridge() before any returns.
  
  (closes issue #19116)
  Reported by: Irontec
  Tested by: rmudgett
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git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@320058 65c4cc65-6c06-0410-ace0-fbb531ad65f3