Merged revisions 300714 via svnmerge from

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

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  r300714 | rmudgett | 2011-01-05 14:54:21 -0600 (Wed, 05 Jan 2011) | 21 lines
  
  Merged revision 300711 from
  https://origsvn.digium.com/svn/asterisk/be/branches/C.3-bier
  
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    r300711 | rmudgett | 2011-01-05 13:43:55 -0600 (Wed, 05 Jan 2011) | 14 lines
  
    A call retrieved from hold may wind up with no audio.
  
    If the retrieved call is natively bridged then the call may not have any
    audio path.  The following warning message is given:
    "Failed to add <dfd> to conference <chan>/<chan>: Invalid argument".
  
    * Open the media on a B channel when pri_fixup_principle() moves the call
    from a no_b_channel channel to a real channel.
  
    * Added lock protection while pri_fixup_principle() moves a call from one
    private structure to another.
  
    * Made some pri_fixup_principle() messages more meaningful.
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git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@300716 65c4cc65-6c06-0410-ace0-fbb531ad65f3