Merged revisions 317196 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.8

........
  r317196 | mnicholson | 2011-05-05 13:02:52 -0500 (Thu, 05 May 2011) | 8 lines
  
  Set SO_KEEPALIVE on SIP TCP sockets so that they eventually go away when a peer
  abruptly disappears.  This mostly occurs after a successful registration.
  
  (closes issue #17544)
  Reported by: marcelloceschia
  Patches:
        (modified) tcptls.patch uploaded by st (license 907)
........


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@317198 65c4cc65-6c06-0410-ace0-fbb531ad65f3