Merged revisions 337008 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/10

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  r337008 | rmudgett | 2011-09-20 14:12:24 -0500 (Tue, 20 Sep 2011) | 22 lines
  
  Merged revisions 337007 via svnmerge from 
  https://origsvn.digium.com/svn/asterisk/branches/1.8
  
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    r337007 | rmudgett | 2011-09-20 14:10:30 -0500 (Tue, 20 Sep 2011) | 15 lines
    
    Check if a channel was created before using the pointer in sig_ss7_new_ast_channel().
    
    Fixes the crash in ASTERISK-17955 gdb-11918.txt backtrace.
    
    * Added some missing libss7 access lock protection.
    
    * Prevent cancelling the ss7_linkset() thread at inoportune times just
    like the pri_dchannel() thread.
    
    (issue ASTERISK-17955)
    Reported by: Ian M Sherman
    Patches:
          jira_asterisk_17955_v1.8.patch (license #5621) patch uploaded by rmudgett
          (attached to related ASTERISK-17966)
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git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@337009 65c4cc65-6c06-0410-ace0-fbb531ad65f3