minor #6880 Remove extra quotes from ExprBuilder::thenInvalid() usage (chalasr)

This PR was merged into the 2.7 branch.

Discussion
----------

Remove extra quotes from ExprBuilder::thenInvalid() usage

The given example gives extra quotes (`Invalid database driver ""value""` instead of (`Invalid database driver "value"`), because the value is automatically quoted due to the use of `json_encode`.

Commits
-------

dd54426 Remove extra quotes from ExprBuilder::thenInvalid() usage

Author: wouterj

components/config/definition.rst

@@ -726,7 +726,7 @@ The builder is used for adding advanced validation rules to node definitions, li
                         ->isRequired()
                         ->validate()
                         ->ifNotInArray(array('mysql', 'sqlite', 'mssql'))
-                            ->thenInvalid('Invalid database driver "%s"')
+                            ->thenInvalid('Invalid database driver %s')
                         ->end()
                     ->end()
                 ->end()