Eliminate deadlock potential in dahdi_fixup().

(This is a backport of 269307, committed to trunk by rmudgett.)

Calling dahdi_indicate() when the channel private lock is already
held can cause a deadlock if the PRI lock is needed because
dahdi_indicate() will also get the channel private lock.  The pri_grab()
function assumes that the channel private lock is held once to avoid
deadlock.

(closes issue #17261)
Reported by: aragon


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@271335 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_dahdi.c

@@ -3938,10 +3938,10 @@ static int dahdi_fixup(struct ast_channel *oldchan, struct ast_channel *newchan)
 				dahdi_unlink(NULL, p, 0);
 			p->subs[x].owner = newchan;
 		}
-	if (newchan->_state == AST_STATE_RINGING) 
-		dahdi_indicate(newchan, AST_CONTROL_RINGING, NULL, 0);
 	update_conf(p);
 	ast_mutex_unlock(&p->lock);
+	if (newchan->_state == AST_STATE_RINGING) 
+		dahdi_indicate(newchan, AST_CONTROL_RINGING, NULL, 0);
 	return 0;
 }