ldap: fixed email extraction typo. An empty

ldap email will now not overwritt the stored one.

rhodecode/authentication/plugins/auth_ldap.py

@@ -444,7 +444,7 b' class RhodeCodeAuthPlugin(RhodeCodeExter'
                 'lastname': safe_unicode(
                     get_ldap_attr('attr_lastname') or lastname),
                 'groups': groups,
-                'email': get_ldap_attr('attr_email' or email),
+                'email': get_ldap_attr('attr_email') or email,
                 'admin': admin,
                 'active': active,
                 "active_from_extern": None,