Fix for unknown configuration option

This should fix #585 

@StudioEcho please review the default filter propositions

is this good:

```yaml
->scalarNode('PHP_ARRAY')->defaultValue('choice')->end() 

->scalarNode('LONGVARCHAR')->defaultValue('text')->end()
->scalarNode('BLOB')->defaultValue('text')->end()
->scalarNode('CLOB')->defaultValue('text')->end()
->scalarNode('CLOB_EMU')->defaultValue('text')->end() 
``` 
?