Allow timeout to reach zero in read_socket_line for one non-blocking read

src/ckpool.c

@@ -536,7 +536,7 @@ int read_socket_line(connsock_t *cs, float *timeout)
 
 	tv_time(&start);
 rewait:
-	if (*timeout <= 0) {
+	if (*timeout < 0) {
 		LOGDEBUG("Timed out in read_socket_line");
 		ret = 0;
 		goto out;
@@ -569,7 +569,7 @@ rewait:
 			if (eom)
 				break;
 			/* Have we used up all the timeout yet? */
-			if (*timeout > 0 && (errno == EAGAIN || errno == EWOULDBLOCK || !ret))
+			if (*timeout >= 0 && (errno == EAGAIN || errno == EWOULDBLOCK || !ret))
 				goto rewait;
 			if (cs->ckp->proxy)
 				LOGINFO("Failed to recv in read_socket_line");