uxtheme: Fix loading a different theme when theming is on.

When a theme is already active and a user tries to activate another theme,
the new theme configuration should be written to the registry so that it's
still in effect after a wine reboot.

Fix a regression introduced in d290362.

Signed-off-by: Zhiyi Zhang <zzhang@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>

dlls/uxtheme/system.c

@@ -446,10 +446,8 @@ HRESULT UXTHEME_SetActiveTheme(PTHEME_FILE tf)
                 WARN("Failed to get LoadedBefore: %d\n", GetLastError());
             RegCloseKey(hKey);
         }
-        if (loaded_before)
-            return MSSTYLES_SetActiveTheme(tf, FALSE);
 
-        if (ret)
+        if (!loaded_before && ret)
             UXTHEME_SaveUnthemedSystemMetrics(&metrics);
     }
     else {