ENT-4149: Change reset administrative credentials documentation

Do not overwrite email and roles in case if admin user exists

(cherry picked from commit 51bf6b4)

enterprise-cfengine-guide/hub_administration/reset-admin-creds.markdown

@@ -10,18 +10,11 @@ The default `admin` user can be reset to defaults using the following SQL.
 cfsettings-setadminpassword.sql:
 
 ```sql
-UPDATE "users"
-	SET password='SHA=aa459b45ecf9816d472c2252af0b6c104f92a6faf2844547a03338e42e426f52',
-	    salt='eWAbKQmxNP',
-	    name='admin',
-	    email='admin@organisation.com',
-	    active='1',
-	    roles='{admin,cf_remoteagent}',
-            changetimestamp = now()
-	WHERE username='admin';
 INSERT INTO "users" ("username", "password", "salt", "name", "email", "external", "active", "roles", "changetimestamp")
        SELECT 'admin', 'SHA=aa459b45ecf9816d472c2252af0b6c104f92a6faf2844547a03338e42e426f52', 'eWAbKQmxNP', 'admin',  'admin@organisation.com', false, '1',  '{admin,cf_remoteagent}', now()
-       WHERE NOT EXISTS (SELECT 1 FROM users WHERE username='admin');
+ON CONFLICT (username, external) DO UPDATE 
+  SET password = 'SHA=aa459b45ecf9816d472c2252af0b6c104f92a6faf2844547a03338e42e426f52', 
+      salt = 'eWAbKQmxNP';
 ```
 
 To reset the CFEngine admin user run the following sql as root on your hub