Avoid applog under cg_wlock.

cgminer.c

@@ -6598,16 +6598,20 @@ static void *test_pool_thread(void *arg)
 	if (pool_active(pool, false)) {
 		pool_tset(pool, &pool->lagging);
 		pool_tclear(pool, &pool->idle);
+		bool first_pool = false;
 
 		cg_wlock(&control_lock);
 		if (!pools_active) {
 			currentpool = pool;
 			if (pool->pool_no != 0)
-				applog(LOG_NOTICE, "Switching to pool %d %s - first alive pool", pool->pool_no, pool->rpc_url);
+				first_pool = true;
 			pools_active = true;
 		}
 		cg_wunlock(&control_lock);
 
+		if (unlikely(first_pool))
+			applog(LOG_NOTICE, "Switching to pool %d %s - first alive pool", pool->pool_no, pool->rpc_url);
+
 		pool_resus(pool);
 	} else
 		pool_died(pool);