gtkmain: Invoke keysnoopers unconditionally

Now that ATK no longer uses a key snooper but is invoked directly,
checking in advance for existing snoopers is wrong and stops ATK from
working.

Also: code reduction without performance loss == good thing.

https://bugzilla.gnome.org/show_bug.cgi?id=669176

gtk/gtkmain.c

@@ -1640,11 +1640,8 @@ gtk_main_do_event (GdkEvent *event)
 
     case GDK_KEY_PRESS:
     case GDK_KEY_RELEASE:
-      if (key_snoopers)
-        {
       if (gtk_invoke_key_snoopers (grab_widget, event))
         break;
-        }
 
       /* make focus visible in a window that receives a key event */
       {