LevelDB Storage Engine: re-commit in git against webscale
Re-commit in Git: Port to RocksDB. Let LevelDB engine be optional.
Also added HTON_SUPPORTS_EXTENDED_KEYS to both engines.
Re-commit in git: fake support for UNIQUE indexes. They can be created for RocksDB but won't be enforced.
re-commit in git:Fix rocksdb to build when bz2 library is present.
Make RocksDB SE compile in webscale.
Re-commit in git: Post-fixes after UNIQUE index support was
enabled without uniqueness enforcement.
- Fix compile warning
- Fix the rocksdb.test/result
Re-commit in git:  Explicit insert into an auto-inc column is not noticed by RocksDB

Basic fix: don't forget to update the table-wide auto-increment value.
Update rocksdb.result after moving from MySQL to webscalesql.