Merged revisions 219303 via svnmerge from

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

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  r219303 | dvossel | 2009-09-17 16:29:37 -0500 (Thu, 17 Sep 2009) | 21 lines
  
  INVITE w/Replaces deadlock fix
  
  This patch cleans up the locking logic in chan_sip.c's
  handle_invite_replaces() function as well as making use
  of ast_do_masquerade() rather than forcing the masquerade
  on an ast_read().  The code had several redundant unlocks
  that would result in 'freed more times than we've locked!'
  errors. I cleaned these up as well as moving all the unlock
  logic to the end of the function.  This patch should also
  resolve the issue people were having with the replacecall
  channel never being unlocked with one legged calls.
  
  (closes issue #15151)
  Reported by: irroot
  Patches:
        invite_w_replaces_1.4.diff uploaded by dvossel (license 671)
  Tested by: irroot, dvossel
  
  Review: https://reviewboard.asterisk.org/r/371/
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git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@219304 65c4cc65-6c06-0410-ace0-fbb531ad65f3