Extend MDEV-13453 workaround explanations

The example SQL now shows the extra grant required for 10.2 versions. Also
removed duplicate user creation examples from the tutorials.

Documentation/Tutorials/Connection-Routing-Tutorial.md

@@ -90,16 +90,8 @@ for the read service we use the _slave_ type.
 
 The final part of the service configuration is the `user` and `password`
 parameters that define the credentials that the service will use to populate the
-user authentication data. To create this user, execute the following SQL commands.
-
-```
-CREATE USER 'maxscale'@'%' IDENTIFIED BY 'maxscale_pw';
-GRANT SELECT ON mysql.user TO 'maxscale'@'%';
-GRANT SELECT ON mysql.db TO 'maxscale'@'%';
-GRANT SELECT ON mysql.tables_priv TO 'maxscale'@'%';
-GRANT SELECT ON mysql.roles_mapping TO 'maxscale'@'%';
-GRANT SHOW DATABASES ON *.* TO 'maxscale'@'%';
-```
+user authentication data. These users were created at the start of the
+[MaxScale Tutorial](MaxScale-Tutorial.md).
 
 **Note:** For increased security [encrypt your passwords in the configuration file](Encrypting-Passwords.md).
 

Documentation/Tutorials/MaxScale-Tutorial.md

@@ -35,6 +35,9 @@ GRANT SELECT ON mysql.db TO 'maxscale'@'%';
 GRANT SELECT ON mysql.tables_priv TO 'maxscale'@'%';
 GRANT SELECT ON mysql.roles_mapping TO 'maxscale'@'%';
 GRANT SHOW DATABASES ON *.* TO 'maxscale'@'%';
+
+-- MariaDB from 10.2.2 to 10.2.10 requires extra grants
+GRANT SELECT ON mysql.* TO 'maxscale'@'%';
 ```
 
 These credentials will be used by the services in MaxScale to populate the user

Documentation/Tutorials/Read-Write-Splitting-Tutorial.md

@@ -72,16 +72,8 @@ or addresses of the servers.
 
 The final part of the service configuration is the `user` and `password`
 parameters that define the credentials that the service will use to populate the
-user authentication data. To create this user, execute the following SQL commands.
-
-```
-CREATE USER 'maxscale'@'%' IDENTIFIED BY 'maxscale_pw';
-GRANT SELECT ON mysql.user TO 'maxscale'@'%';
-GRANT SELECT ON mysql.db TO 'maxscale'@'%';
-GRANT SELECT ON mysql.tables_priv TO 'maxscale'@'%';
-GRANT SELECT ON mysql.roles_mapping TO 'maxscale'@'%';
-GRANT SHOW DATABASES ON *.* TO 'maxscale'@'%';
-```
+user authentication data. These users were created at the start of the
+[MaxScale Tutorial](MaxScale-Tutorial.md).
 
 **Note:** For increased security [encrypt your passwords in the configuration file](Encrypting-Passwords.md).