Tests: Remove usage of krb5 ccache from test_ipaserver/test_ldap
In test_ipaserver/test_ldap::test_ldap::test_GSSAPI a krb5 ccache is used to
connect to ldap. The test tries to locate this cache in /tmp/krb5cc_$UID file,
which is not there due to default settings in krb5.conf, and hence the whole
test is skipped. Fix the test to use keyring to connect instead of ccache in
/tmp.
https://fedorahosted.org/freeipa/ticket/6323
Reviewed-By: Martin Basti <mbasti@redhat.com>