date-selector: update text even for today

When the date selector is initialized, the text is
blank, even when the date is set for today.

Fix that by updating the text when setting the date.

src/gcal-date-selector.c

@@ -259,6 +259,7 @@ gcal_date_selector_set_date (GcalDateSelector *selector,
 
   /* set calendar's date */
   gcal_date_chooser_set_date (GCAL_DATE_CHOOSER (selector->date_chooser), date);
+  update_text (selector);
 
   /* emit the MODIFIED signal */
   g_object_notify (G_OBJECT (selector), "date");