Revert "gdbus-connection-loss: Fix leak in test"

This reverts commit 670379b26f.

This is causing distcheck to fail and will have to be revisited later.

gio/tests/gdbus-connection-loss.c

@@ -139,10 +139,7 @@ main (int   argc,
 
   ret = g_test_run();
 
-  session_bus_down ();
-
   g_object_unref (c);
-  g_main_loop_unref (loop);
 
   return ret;
 }