Fix managed rawfilestore

This PR was previously a part of https://github.com/openmicroscopy/openmicroscopy/pull/2242

The use of `ManagedRawFileStoreI.java` was never properly implemented so that the close/re-open logic needed by 2242 never worked. This should have zero impact on the existing code base. Only when clients start actively calling `getUploader().close() && getUploader()` should a difference be seen. Previously (as in 2242) this would throw an `ObjectNotExistException` since the `RawFileStorePrx` was being held on to. With this, the RFS should be re-opened.