avoid leaking Ark creds from local build into site.yml

Author: sjpb

environments/common/files/grafana/grafana.repo.j2

@@ -5,7 +5,7 @@ enabled = 0
 name = grafana
 async = 1
 gpgcheck = 0
-{% if dnf_repos_password is defined %}
+{% if 'dnf_repos' in groupnames and dnf_repos_password is defined %}
 password = {{ dnf_repos_password }}
 username = {{ dnf_repos_username }}
 {% endif %}