IPA_ACCESS: Make ipa_purge_hbac() more generic
This mothod can also be reused in the future for new backend modules.
In order to make it more generic, let's just move it to
ipa_rules_common.[ch], rename it to ipa_common_purge_rules() and make
the subtreename to be purged a new paramether of this method.
Signed-off-by: Fabiano Fidêncio <email@example.com>
Reviewed-by: Pavel Březina <firstname.lastname@example.org>
Reviewed-by: Jakub Hrozek <email@example.com>