Orphan removal

Hi,

I created 2 tests to show that we encounter a problem when using orphanRemoval (see https://github.com/raziel057/doctrine2/commit/e0365f0d1837edc2459990041398ade472354e5e).

-> The ActionLog is created with no value in the "action" column.

That's not the case when removing manually (see https://github.com/raziel057/doctrine2/commit/62fbf49654b3ea751bec824e9a047d45aa899b7a).

-> The ActionLog is created with value "remove" in the "action" column.

I think the behavior must be the same in the 2 Tests.

For information, I discovered the problem when using https://github.com/KnpLabs/DoctrineBehaviors/blob/master/src/Knp/DoctrineBehaviors/ORM/Loggable/LoggableListener.php with a custom callable DB logger.