Capped percent complete in monitor.c (#825)

* phillip/823: capped percent complete

* Compile :(

* phillip/823: fixed issue closer to source

* phillip/823: cleanup code and reduce unnecessary loops

* phillip/823: compile

* phillip/823: comment nit

src/monitor.c

@@ -158,9 +158,19 @@ double compute_remaining_time(double age, uint64_t packets_sent,
 			remaining[4] =
 			    (1. - done) * (age / done) + zconf.cooldown_secs;
 		}
-		return min_d(remaining, sizeof(remaining) / sizeof(double));
+		double remaining_time = min_d(remaining, sizeof(remaining) / sizeof(double));
+		if (remaining_time < 0) {
+			// remaining time cannot be less than zero
+			return 0;
+		}
+		return remaining_time;
 	} else {
-		return zconf.cooldown_secs - (now() - zsend.finish);
+		double remaining_time = zconf.cooldown_secs - (now() - zsend.finish);
+		if (remaining_time < 0) {
+			// remaining time cannot be less than zero
+			return 0;
+		}
+		return remaining_time;
 	}
 }