disable map when unsetting zoomap child

if the existing map is left enabled when the child is removed from the
zoomap, the child object will be permanently misrendered with the previously
applied map

src/bin/e_zoomap.c

@@ -50,6 +50,8 @@ e_zoomap_child_set(Evas_Object *obj, Evas_Object *child)
    if (child == sd->child_obj) return;
    if (sd->child_obj)
      {
+        evas_object_map_set(sd->child_obj, NULL);
+        evas_object_map_enable_set(sd->child_obj, EINA_FALSE);
         evas_object_clip_unset(sd->child_obj);
         evas_object_smart_member_del(sd->child_obj);
         evas_object_event_callback_del(sd->child_obj, EVAS_CALLBACK_DEL,