LDAP auth: make flake8 happy

"fix" small lint to keep flake8 happy.

radicale/auth/ldap.py

@@ -216,7 +216,7 @@ class Auth(auth.BaseAuth):
                 """Fill groupDNs with DNs of groups found"""
                 if len(res) > 0:
                     groupDNs = []
-                    for dn,entry in res:
+                    for dn, entry in res:
                         groupDNs.append(dn)
 
             """Close LDAP connection"""