Fix the "failed" extension for outgoing calls.

The conversion to use ast_check_hangup() everywhere instead of checking the softhangup
flag directly introduced this problem.  The issue is that ast_check_hangup() checked
for tech_pvt to be NULL.  Unfortunately, this will be NULL is some valid circumstances,
such as with a dummy channel.

The fix is simple.  Don't check tech_pvt.  It's pointless, because the code path that
sets this to NULL is when the channel hangup callback gets called.  This happens inside
of ast_hangup(), which is the same function responsible for freeing the channel.  Any
code calling ast_check_hangup() better not be calling it after that point, and if so,
we have a bigger problem at hand.

(closes issue #14035)
Reported by: erogoza


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@163171 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/channel.c

@@ -461,8 +461,6 @@ int ast_check_hangup(struct ast_channel *chan)
 {
 	if (chan->_softhangup)		/* yes if soft hangup flag set */
 		return 1;
-	if (!chan->tech_pvt)		/* yes if no technology private data */
-		return 1;
 	if (ast_tvzero(chan->whentohangup))	/* no if no hangup scheduled */
 		return 0;
 	if (ast_tvdiff_ms(chan->whentohangup, ast_tvnow()) > 0) 	/* no if hangup time has not come yet. */