pytest/testlib: Fix related to removing kerberos database
Stop krb5kdc and kadmin services. Earlier we were
not stopping kadmin services. The current code use
loop to stop the services
Based on review comments, used tuple to define krb5kdc and kadmin
Signed-off-by: Niranjan M.R <mrniranjan@redhat.com>
Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>