increment patch version for 5.7.1

fix deletion dropping in intra-L0

Summary:
`KeyNotExistsBeyondOutputLevel` didn't consider L0 files' key-ranges. So if a key only was covered by older L0 files' key-ranges, we would incorrectly drop deletions of that key. This PR just skips the deletion-dropping optimization when output level is L0.
Closes https://github.com/facebook/rocksdb/pull/2726

Differential Revision: D5617286

Pulled By: ajkr

fbshipit-source-id: 4bff1396b06d49a828ba4542f249191052915bce

Move blob_db/ttl_extractor.h into blob_db/blob_db.h

Summary:
Move blob_db/ttl_extractor.h into blob_db/blob_db.h
Also exclude TTLExtractor from LITE build.
Closes https://github.com/facebook/rocksdb/pull/2665

Differential Revision: D5520009

Pulled By: yiwu-arbug

fbshipit-source-id: 4813dcc272c7cc4bf2cdac285256d9a17d78c7b7

Blob DB TTL extractor

Summary:
Introducing blob_db::TTLExtractor to replace extract_ttl_fn. The TTL
extractor can be use to extract TTL from keys insert with Put or
WriteBatch. Change over existing extract_ttl_fn are:
* If value is changed, it will be return via std::string* (rather than Slice*). With Slice* the new value has to be part of the existing value. With std::string* the limitation is removed.
* It can optionally return TTL or expiration.

Other changes in this PR:
* replace `std::chrono::system_clock` with `Env::NowMicros` so that I can mock time in tests.
* add several TTL tests.
* other minor naming change.
Closes https://github.com/facebook/rocksdb/pull/2659

Differential Revision: D5512627

Pulled By: yiwu-arbug

fbshipit-source-id: 0dfcb00d74d060b8534c6130c808e4d5d0a54440

Reduce blob db noisy logging

Summary:
Remove some of the per-key logging by blob db to reduce noise.
Closes https://github.com/facebook/rocksdb/pull/2587

Differential Revision: D5429115

Pulled By: yiwu-arbug

fbshipit-source-id: b89328282fb8b3c64923ce48738c16017ce7feaf

Update java/rocksjni.pom

Summary: Closes https://github.com/facebook/rocksdb/pull/2610

Differential Revision: D5445705

Pulled By: siying

fbshipit-source-id: d5f97ffdf5bc18b853c3a106755aca96a650e428

Remove some left-over BSD headers

Summary: Closes https://github.com/facebook/rocksdb/pull/2608

Differential Revision: D5444797

Pulled By: siying

fbshipit-source-id: 690581d03f37822e059a16085088e8e2d8a45016

Add back the LevelDB license file

Summary: Closes https://github.com/facebook/rocksdb/pull/2591

Differential Revision: D5432696

Pulled By: siying

fbshipit-source-id: a613230ab916de0b279a65ef429ede65460a8db2

Remove the licensing description in CONTRIBUTING.md

Summary: Closes https://github.com/facebook/rocksdb/pull/2590

Differential Revision: D5432539

Pulled By: siying

fbshipit-source-id: 49902453bba3c95c1fb8354441b2198649e52bf4

Change RocksDB License

Summary: Closes https://github.com/facebook/rocksdb/pull/2589

Differential Revision: D5431502

Pulled By: siying

fbshipit-source-id: 8ebf8c87883daa9daa54b2303d11ce01ab1f6f75