Fix timer handling

ev_timer_time may remain the same for legit reason, so to prevent looping, instead, reset it before invoking the handler.
To let user know what the initial setting was, pass it as the argument instead of current time (which is kind of pointless).

PUBLISHED_FROM=fa328009f097f9b49b5b0dd13a38ee6d6e6518de

mongoose.c

@@ -2270,14 +2270,8 @@ MG_INTERNAL void mg_call(struct mg_connection *nc,
 void mg_if_timer(struct mg_connection *c, double now) {
   if (c->ev_timer_time > 0 && now >= c->ev_timer_time) {
     double old_value = c->ev_timer_time;
-    mg_call(c, NULL, c->user_data, MG_EV_TIMER, &now);
-    /*
-     * To prevent timer firing all the time, reset the timer after delivery.
-     * However, in case user sets it to new value, do not reset.
-     */
-    if (c->ev_timer_time == old_value) {
-      c->ev_timer_time = 0;
-    }
+    c->ev_timer_time = 0;
+    mg_call(c, NULL, c->user_data, MG_EV_TIMER, &old_value);
   }
 }