Add some necessary hangup commands in the case that forwarding

a call fails

1) Hang up the original destination if the local channel cannot
   be requested.
2) Hang up the local channel (in addition to the original destination)
   if ast_call fails when calling the newly created local channel.

This prevents channels from sticking around forever in the
case of a botched call forward (e.g. to an extension which does not
exist).

(closes issue #13764)
Reported by: davidw
Patches:
      13764_v2.patch uploaded by putnopvut (license 60)
Tested by: putnopvut, davidw



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@159554 65c4cc65-6c06-0410-ace0-fbb531ad65f3