Remove an explicit destroy to the ClutterText actor

This is the same as the previous commit, but for StEntry.
We don't have any need to explicitly destroy this actor in our dispose
implementation, and doing so breaks the assumption that we can access
the clutter_text from within destroy.

https://bugzilla.gnome.org/show_bug.cgi?id=783483

src/st/st-entry.c

@@ -230,12 +230,6 @@ st_entry_dispose (GObject *object)
   StEntryPrivate *priv = ST_ENTRY_PRIV (entry);
   GdkKeymap *keymap;
 
-  if (priv->entry)
-    {
-      clutter_actor_destroy (priv->entry);
-      priv->entry = NULL;
-    }
-
   keymap = gdk_keymap_get_for_display (gdk_display_get_default ());
   g_signal_handlers_disconnect_by_func (keymap, keymap_state_changed, entry);