Set Longer STUN Timeout
We were having an issue with outbound Jingle calls where it would fail
to establish a connection.
It appeared to be a bug in pjproject, specifically that they don't
retrigger failed triggered checks, and the call receiver started sending
checks before the call initiator (because they receive that info on call
acceptance), so there was plenty of time for things to fail before we
even had a chance.
This does not fix that bug, but by extending the window of time it
retries before declaring failure, we can step around it a little.