commit 394d0712d3d46a87a8063e14e998e9c22336e3a6
Author: Anca Agape <anca@fb.com>
Date:   Thu Jul 27 15:43:07 2017 -0700

    Fix rpl.rpl_4threads_deadlock test broken by D5005670

    Summary:
    In D5005670 in fill_fields_processlist() function we introduced a point
    where we were trying to take the LOCK_thd_data before the
    synchronization point used by test
    processlist_after_LOCK_thd_count_before_LOCK_thd_data. This was
    happening in get_attached_srv_session() function called. Replaced this
    with get_attached_srv_session_safe() and moved it after lock is aquired.

    Reviewed By: tianx

    Differential Revision: D5505992

    fbshipit-source-id: bc53924