Fix an issue where cancelled outgoing SIP calls would erroneously report the device...

Fix an issue where cancelled outgoing SIP calls would erroneously report the device as "in use."

A user was having an issue where if an outgoing SIP call was canceled, the SIP device
would remain in use if we had not received any response to the initial INVITE we sent out.
The SIP device would remain in use until the autocongestion timer was exhausted.

I tracked down the cause of this to be the section of code I am removing here. I asked several
people what the purpose of this code was meant to be, but no one could give me any sort of
answer as to why this was here. The person who was having this issue has been using this patch
for several months and it has stopped the problems they have had.

AST-196

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@183115 65c4cc65-6c06-0410-ace0-fbb531ad65f3