Fix app_dial ring groups

Revert part of r315643. We need to remove the datastore here as well.
The code in bridging code will catch anything that app_dial might miss.

(closes issue #19311)
Reported by: mspuhler
Patches: 
      issue_19311_no_answer.diff uploaded by elguero (license 37)


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@319527 65c4cc65-6c06-0410-ace0-fbb531ad65f3

apps/app_dial.c

@@ -1453,6 +1453,17 @@ static int dial_exec_full(struct ast_channel *chan, void *data, struct ast_flags
 	time(&start_time);
 	peer = wait_for_answer(chan, outgoing, &to, peerflags, &sentringing, status, sizeof(status), numbusy, numnochan, numcongestion, ast_test_flag(&opts, OPT_PRIORITY_JUMP), &result);
 
+	/* The ast_channel_datastore_remove() function could fail here if the
+	 * datastore was moved to another channel during a masquerade. If this is
+	 * the case, don't free the datastore here because later, when the channel
+	 * to which the datastore was moved hangs up, it will attempt to free this
+	 * datastore again, causing a crash
+	 */
+	ast_channel_lock(chan);
+	if (!ast_channel_datastore_remove(chan, datastore)) {
+		ast_channel_datastore_free(datastore);
+	}
+	ast_channel_unlock(chan);
 	if (!peer) {
 		if (result) {
 			res = result;