Merged revisions 238411 via svnmerge from

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

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  r238411 | dvossel | 2010-01-07 14:14:25 -0600 (Thu, 07 Jan 2010) | 10 lines
  
  fixes crash in "scheduled_destroy" in chan_iax
  
  A signed short was used to represent a callnumber.  This is makes
  it possible to attempt to access the iaxs array with a negative
  index.
  
  (closes issue #16565)
  Reported by: jensvb
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git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@238412 65c4cc65-6c06-0410-ace0-fbb531ad65f3