removing pointless calls on quoteIdentifier() - reason: name on $tableDi...

...ff doesn't exist and my design the name cannot be changed:
````
PHP Notice:  Undefined property: Doctrine\DBAL\Schema\Table::$name in /home/deepdiver/Development/ownCloud/core/lib/private/db/mdb2schemamanager.php on line 82
PHP Stack trace:
PHP   1. {main}() /home/deepdiver/Development/ownCloud/core/occ:0
PHP   2. require_once() /home/deepdiver/Development/ownCloud/core/occ:11
PHP   3. Symfony\Component\Console\Application->run() /home/deepdiver/Development/ownCloud/core/console.php:34
PHP   4. Symfony\Component\Console\Application->doRun() /home/deepdiver/Development/ownCloud/core/3rdparty/symfony/console/Symfony/Component/Console/Application.php:121
PHP   5. Symfony\Component\Console\Application->doRunCommand() /home/deepdiver/Development/ownCloud/core/3rdparty/symfony/console/Symfony/Component/Console/Application.php:191
PHP   6. Symfony\Component\Console\Command\Command->run() /home/deepdiver/Development/ownCloud/core/3rdparty/symfony/console/Symfony/Component/Console/Application.php:897
PHP   7. OC\Core\Command\Db\GenerateChangeScript->execute() /home/deepdiver/Development/ownCloud/core/3rdparty/symfony/console/Symfony/Component/Console/Command/Command.php:244
PHP   8. OC\DB\MDB2SchemaManager->updateDbFromStructure() /home/deepdiver/Development/ownCloud/core/core/command/db/generatechangescript.php:38
````

adding PHPDoc