propsys/tests: Fix a memory leak (Valgrind).

Signed-off-by: Sven Baars <sven.wine@gmail.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>

dlls/propsys/tests/propstore.c

@@ -214,6 +214,7 @@ static void test_persistserialized(void)
 
     if (FAILED(hr))
     {
+        IPropertyStore_Release(propstore);
         skip("IPersistSerializedPropStorage not supported\n");
         return;
     }