Don't completely error out if a config file for chan_phone was not found. (issue #7710 reported by Mithraen)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@39513 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_phone.c

@@ -1345,7 +1345,7 @@ static int load_module(void *mod)
 	/* We *must* have a config file otherwise stop immediately */
 	if (!cfg) {
 		ast_log(LOG_ERROR, "Unable to load config %s\n", config);
-		return -1;
+		return 0;
 	}
 	if (ast_mutex_lock(&iflock)) {
 		/* It's a little silly to lock it, but we mind as well just to be sure */