attended transfers: Fix a bug affecting external blond transfers

Performing a blond transfer (attended transfer that is completed
before the transfer recipient picks up) externally through chan_sip
or chan_pjsip would result in lost references to the channels
involved with the transfer as well as their bridge.

(closes issue ASTERISK-22092)
Reported by: mmichelson
Review: https://reviewboard.asterisk.org/r/2766/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@396923 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/bridge.c

@@ -4277,7 +4277,7 @@ enum ast_transfer_result ast_bridge_transfer_attended(struct ast_channel *to_tra
 	ast_bridge_remove(the_bridge, chan_bridged);
 
 	publish_attended_transfer_app(&publication, app);
-	return AST_BRIDGE_TRANSFER_SUCCESS;
+	res = AST_BRIDGE_TRANSFER_SUCCESS;
 
 end:
 	/* All successful transfer paths have published an appropriate stasis message.