month-view: correctly check if dates are different

The previous commit introduced many changes in the way
the conditions are done. Unfortunately, one of these
conditions was only partially fixed.

Fix that by using the correct function to compare dates.

src/gcal-month-view.c

@@ -288,7 +288,7 @@ show_popover_for_position (GcalMonthView *view,
         }
 
       /* Only setup an end date when days are different */
-      if (!g_date_time_compare (start_dt, end_dt))
+      if (!g_date_time_equal (start_dt, end_dt))
         {
           GDateTime *tmp_dt;