With this change we are switching methods to begin object, from
BeginObjectExactVersion to BeginObjectNextVersion. Main implication
is that from now it will be possible to have object with version
different than 1. New object will always get first available version.
Main reason to do this it to avoid deleting existing object during
reuploading object. Now we can create multiple pending objects but
only last committed will be available to the user. Any previous
committed object will be deleted.Because of that we moved logic to
delete existing object from BeginObject to CommitoObject request.
New logic is behind feature flat to be able to test it well first
before enablng on production.
Fixes https://github.com/storj/storj/issues/4871
Change-Id: I2dd9c7364fd93796a05ef607bda9c39a741e6a89
4d9c9138ce