ipa-server-upgrade: fix add_systemd_user_hbac
During upgrade, the method add_systemd_user_hbac is creating
a hbacsvc and a hbacrule, but fails in python2 because of
unicode conversion errors.
The arguments should be defined as u'value'.
Fixes: https://pagure.io/freeipa/issue/7896
Reviewed-By: Christian Heimes <cheimes@redhat.com>