log: add LOG_INFO message about suspended stratum to stratum_rthread().

Also a minor style/syntax fix while searching for why pools don't
restart if gone "dead". A pool is considered "dead" if pool->idle
is true.

sgminer.c

@@ -5260,6 +5260,8 @@ static void *stratum_rthread(void *userdata)
 		 * indefinitely or just bring it up when we switch to this
 		 * pool */
 		if (!sock_full(pool) && !cnx_needed(pool)) {
+			applog(LOG_INFO, "Suspending stratum on %s",
+			       pool->poolname);
 			suspend_stratum(pool);
 			clear_stratum_shares(pool);
 			clear_pool_work(pool);