Created attachment 322317 [details] [review]
Run gs_plugin_loader_refine_func only if PackageKit is available

The tests in "gs_plugin_loader_refine_func" only do anything meaningful if PackageKit is available, so the test shouldn't be run if it isn't.

Note that there are more ways of bypassing this. I could add the check around the call that loads the plugin and return if it wasn't loaded but since this is the only plugin call inside the function, there's no point in running it if it will do nothing.
In the future, if we add other refine plugins, we can enable the function.