Apply this patch from upstream:

commit 2c8deddfb67f1cd41ea3d1ac95aa1aa9327e3406
Author: Yoshinori Matsunobu <yoshinorim@users.noreply.github.com>
Date:   Tue Aug 15 16:21:58 2017 -0700

    Set exclusive_manual_compaction = false on manual compactions

    Summary:
    Combining exclusive manual compaction and
    non-exclusive manual compaction may hit rocksdb assertion errors.
    This diff makes all MyRocks internal manual compactions non exclusive.
    Closes https://github.com/facebook/mysql-5.6/pull/682

    Differential Revision: D5633619

    Pulled By: yoshinorim

    fbshipit-source-id: a90786d