Summary:
This diff does two things:
(1) Log::Reader does not report a corruption when the last record in a log or manifest file is truncated (meaning that log writer died in the middle of the write). Inherited the code from LevelDB: https://code.google.com/p/leveldb/source/detail?r=269fc6ca9416129248db5ca57050cd5d39d177c8#
(2) Turn off mmap writes for all writes to log and manifest files

(2) is necessary because if we use mmap writes, the last record is not truncated, but is actually filled with zeros, making checksum fail. It is hard to recover from checksum failing.

Test Plan:
Added unit tests from LevelDB
Actually recovered a "corrupted" MANIFEST file.

Reviewers: dhruba, haobo

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16119

Summary:
This is not a generic thread local implementation in the sense that it
only takes pointer. But it does support multiple instances per thread
and lets user plugin function to perform cleanup when thread exits or an
instance gets destroyed.

Test Plan: unit test for now

Reviewers: haobo, igor, sdong, dhruba

Reviewed By: igor

CC: leveldb, kailiu

Differential Revision: https://reviews.facebook.net/D16131

Summary: Added a bit more information to compaction context, requested by internal team at FB.

Test Plan: Modified CompactionFilter test to make sure is_manual_compaction is properly set.

Reviewers: haobo

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16095

Remove the unnecessary line led from branch merge.

Summary:
Patch  https://reviews.facebook.net/D15591 enabled checksum
verification by default. This caused the unit test to fail.

Test Plan: ./corruption_test

Reviewers: igor, kailiu

Reviewed By: igor

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15795

Summary:
Easy thing goes first. This patch moves arena to internal dir; based
on which, the coming patch will deal with memtable_rep.

Test Plan: make check

Reviewers: haobo, sdong, dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15615

Summary:
* Add a change log for rocksdb releases.
* Remove the hacky parts of make_new_version.sh, which are either
  no longer useful or will be done in our dedicated 3rd-party release
  tool.

Test Plan: N/A

Reviewers: igor, haobo, sdong, dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15543