Improve and increase debug messages for dying services and scripts

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

src/sig.c

@@ -513,7 +513,7 @@ static void sigchld_cb(uev_t *w, void *arg, int events)
 			break;
 		}
 
-		dbg("Collected child %d", pid);
+		dbg("Collected child %d, status: %d", pid, status);
 		service_monitor(pid, status);
 	}
 }