Remove comment that no longer applies

The monitor thread is already properly torn down on unload and load
failure.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@395619 65c4cc65-6c06-0410-ace0-fbb531ad65f3

res/res_sip.c

@@ -1789,7 +1789,6 @@ error:
 		ast_pjsip_endpoint = NULL;
 	}
 	pj_caching_pool_destroy(&caching_pool);
-	/* XXX Should have a way of stopping monitor thread */
 	return AST_MODULE_LOAD_DECLINE;
 }