Merged revisions 328608 via svnmerge from

Merged revisions 328608 via svnmerge from
https://origsvn.digium.com/svn/asterisk/branches/1.8

........
  r328608 | markm | 2011-07-18 08:35:57 -0400 (Mon, 18 Jul 2011) | 9 lines

  If the sip private structure is null, sip_setoption() will defref the null pointer and crash.

  Ideally, sip_setoption shouldn't be called if there is a lack of a sip private structure.  But this will fix a crash.

  (closes issue ASTERISK-17909)
  Reported by: Mark Murawski
  Tested by: Mark Murawski
........

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.10@328611 65c4cc65-6c06-0410-ace0-fbb531ad65f3