Tasks: Ensure ICalTime::zone is set for current time

Without having set correct time zone for the ICalTime the conversion
routines can convert time twice into the destination time zone,
which causes wrong time. It could be seen also when comparing
the current time with the component time.

Related to libical/libical#571

src/calendar/gui/e-cal-model-tasks.c

@@ -363,6 +363,7 @@ get_due_status (ECalModelTasks *model,
 			}
 
 			now_tt = i_cal_time_new_current_with_zone (zone);
+			i_cal_time_set_timezone (now_tt, zone);
 
 			if (i_cal_time_compare (due_tt, now_tt) <= 0)
 				res = E_CAL_MODEL_TASKS_DUE_OVERDUE;

src/calendar/gui/e-to-do-pane.c

@@ -906,6 +906,7 @@ etdp_get_comp_colors (EToDoPane *to_do_pane,
 			etdp_itt_to_zone (itt, e_cal_component_datetime_get_tzid (dt), client, default_zone);
 
 			now = i_cal_time_new_current_with_zone (default_zone);
+			i_cal_time_set_timezone (now, default_zone);
 
 			if ((is_date && i_cal_time_compare_date_only (itt, now) <= 0) ||
 			    (!is_date && i_cal_time_compare (itt, now) <= 0)) {
@@ -1485,6 +1486,7 @@ etdp_check_time_changed (EToDoPane *to_do_pane,
 
 	zone = e_cal_data_model_get_timezone (to_do_pane->priv->events_data_model);
 	itt = i_cal_time_new_current_with_zone (zone);
+	i_cal_time_set_timezone (itt, zone);
 	new_today = etdp_create_date_mark (itt);
 
 	if (force_update || new_today != to_do_pane->priv->last_today) {
@@ -1924,6 +1926,7 @@ etdp_new_common (EToDoPane *to_do_pane,
 				time_divisions_secs = g_settings_get_int (settings, "time-divisions") * 60;
 				zone = e_cal_data_model_get_timezone (to_do_pane->priv->events_data_model);
 				now = i_cal_time_new_current_with_zone (zone);
+				i_cal_time_set_timezone (now, zone);
 
 				i_cal_time_set_year (now, date_mark / 10000);
 				i_cal_time_set_month (now, (date_mark / 100) % 100);