Edje load: reset seats counter on file_del

The seats list got emptied, but the counter progression was kept,
causing needless different seat names for the same device across
different edje objects.

src/lib/edje/edje_load.c

@@ -2105,6 +2105,7 @@ _edje_file_del(Edje *ed)
              eina_stringshare_del(seat->name);
              free(seat);
           }
+        ed->seats_count = 0;
      }
 
    if (ed->L) _edje_lua2_script_shutdown(ed);