Summary:
The patch adjusts the definition of BlobDB's DB properties a bit by
switching to `GetBlobFileSize` from `GetTotalBlobBytes`. The
difference is that the value returned by `GetBlobFileSize` includes
the blob file header and footer as well, and thus matches the on-disk
size of blob files. In addition, the patch removes the `Version` number
from the `blob_stats` property, and updates/extends the unit tests a little.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8902
Test Plan: `make check`
Reviewed By: riversand963
Differential Revision: D30859542
Pulled By: ltamasi
fbshipit-source-id: e3426d2d567bd1bd8c8636abdafaafa0743c854c
306b779957