[RocksDB] Fix unit test

Summary: fix a bug in D19047, which caused  DBTest.RecoverDuringMemtableCompaction to fail.

Test Plan: unit test

Reviewers: sdong, igor

Reviewed By: igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D19155
bug fix: iteration over ColumnFamilySet needs to be under mutex

Summary: asan_crash_test is failing on segfault

Test Plan: running asan_crash_test

Reviewers: sdong, igor

Reviewed By: igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D19149
fix make shared_lib compilation error

Summary: s/class ParsedInternalKey/struct ParsedInternalKey

Test Plan: make shared_lib

Reviewers: igor, yhchiang, sdong, haobo

Reviewed By: haobo

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D19173