MXS-2393 Fix masking test

The masking_user test creates a database over a masked connection.
As 'CREATE DATABASE DB' is not fully parsed the test will fail since
it creates a database.

To allow the test to pass, we turn off the strict requirement that
all statements must be fully parsed.

maxscale-system-test/cnf/maxscale.cnf.template.masking_mysqltest

@@ -71,6 +71,7 @@ socket=default
 type=filter
 module=masking
 rules=/###access_homedir###/masking_rules.json
+require_fully_parsed=false
 
 [server1]
 type=server