Summary:
`bool BackupableDBOptions::new_naming_for_backup_files` is updated to `BackupTableNameOption BackupableDBOptions::share_files_with_checksum_naming`, where `BackupTableNameOption` is an `enum` type with two enumerators `kChecksumAndFileSize` and `kChecksumAndFileSize`. This opens up possibilities of extenting the current naming scheme for backup table files. By default, `BackupTableNameOption BackupableDBOptions::share_files_with_checksum_naming` is set to `kChecksumAndDbSessionId`.
Revert `BackupEngine::VerifyBackup` to only check file sizes by default.
Also fix the construction of the `SstFileDumper` in `GetFileDbIdentities` by setting a proper `Env` of the `Options` passed in the constructor.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7032
Test Plan: make check
Reviewed By: ajkr
Differential Revision: D22237763
Pulled By: gg814
fbshipit-source-id: 466902a4e731babd64e30f0e82ca1aa82962e52e