Summary:
Basic test cases:
- Manifest is lost or corrupt
- Manifest refers to too many or too few SST files
- SST file is corrupt
- Unflushed data is present when RepairDB is called
Depends on D55065 for its CreateFile() function in file_utils
Test Plan: Ran the tests.
Reviewers: IslamAbdelRahman, yhchiang, yoshinorim, sdong
Reviewed By: sdong
Subscribers: leveldb, andrewkr, dhruba
Differential Revision: https://reviews.facebook.net/D55485
