Fix multiple uninstallation of server
"ipa-server-install --uninstall" no longer fails with error message
"'Env' object has no attribute 'basedn'" when executed on a system that
has no freeIPA server installation.
Fixes: https://pagure.io/freeipa/issue/7063
Signed-off-by: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Felipe Volpone <fbarreto@redhat.com>