Never update counter label if widget has been removed

On Windows it triggers a SIGSEGV.

issue11395
review423491003
(grafted from d0764ce2fbebd20fdbcf6177fa51c6f9e3293755)

--HG--
branch : 6.0

tryton/gui/window/view_form/view/form_gtk/state_widget.py

@@ -193,7 +193,7 @@ class Link(StateMixin, Gtk.Button):
                         counter=counter, label=label))
 
     def _set_count(self, value, idx=0, current=None, counter=None, label=''):
-        if current != self._current and not self.get_parent():
+        if current != self._current or not self.get_parent():
             return
         try:
             counter[idx] = value()