Recorded merge of revisions 223692 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.4

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  r223692 | kpfleming | 2009-10-12 10:30:40 -0500 (Mon, 12 Oct 2009) | 13 lines
  
  Remove automatic switching from T.38 to voice mode in chan_sip.
    
  chan_sip has some code to automatically switch from T.38 mode to voice mode when
  a voice frame is written to the channel while it is in T.38 mode; this was
  intended to handle the situation when a FAX transmission has ended and the channel
  is not yet hung up, but is causing problems at the beginning of FAX sessions as
  well when there are still voice frames 'in flight' at the time the T.38 negotiation
  completes. This patch removes the automatic switchover.
    
  (issue #16025)
  Reported by: jamicque
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git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@223693 65c4cc65-6c06-0410-ace0-fbb531ad65f3