Don't purge read-only marked table

[Superkooka]

It makes no sense to purge tables marked as read-only

[greg0ire]

Thanks @Superkooka !

[stof]

This is wrong to me. Doctrine ORM's readOnly in metadata does not actually mean that the ORM only reads in it (yes, this naming is crappy). The ORM will happily insert or delete from that table if you use $em->persist() or $em->remove(). The only thing it will not do is updating objects that it has read from the DB.

In a sense, this is similar to readonly properties in PHP: you can still write to them once or unset them.

[greg0ire]

Let me revert this then.