ipa-setup-kra: fix python2 parameter
ipa-setup-kra is failing in python2 with
invalid 'role_servrole': must be Unicode text
because of a unicode conversion error.
The method api.Command.server_role_find is called with the parameter
role_servrole='IPA master' but it should rather be
role_servrole=u'IPA master'
Fixes: https://pagure.io/freeipa/issue/7897
Reviewed-By: Christian Heimes <cheimes@redhat.com>