Allow stratum to startup without notify but check it is valid before creating stratum work.

cgminer.c

@@ -6891,7 +6891,7 @@ begin_bench:
 		pool = select_pool(lagging);
 retry:
 		if (pool->has_stratum) {
-			while (!pool->stratum_active) {
+			while (!pool->stratum_active || !pool->stratum_notify) {
 				struct pool *altpool = select_pool(true);
 
 				sleep(5);

util.c

@@ -1314,9 +1314,6 @@ bool auth_stratum(struct pool *pool)
 		goto out;
 	}
 
-	if (!pool->stratum_notify)
-		goto out;
-
 	ret = true;
 	applog(LOG_INFO, "Stratum authorisation success for pool %d", pool->pool_no);
 	pool->probed = true;