glib's 'g_autoslist()' doesn't support lists of 'char *' strings. Add a
type alias 'virGSListString' so that we can register an 'autoptr'
function for it for simple usage of GSList with strings.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>