pagure: explicitely undefine the ADMIN_GROUP variable

Otherwise it goes back to using sysadmin-main which is the default
value, while here we want to rely on a list of users, not a group.

Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr>

roles/pagure/templates/pagure.cfg

@@ -31,6 +31,7 @@ FAS_OPENID_ENDPOINT = 'https://id.stg.fedoraproject.org/openid/'
 DB_URL = 'postgresql://{{ pagure_db_user }}:{{ pagure_db_pass }}@{{ pagure_db_host }}/{{ pagure_db_name }}'
 
 ### The FAS group in which the admin of pagure are
+ADMIN_GROUP = ""
 PAGURE_ADMIN_USERS = ["pingou", "kevin", "smooge"]
 
 # The publicly visible admin email address