Revert "FileStore: fix OpSequencer::flush error"
Revert "FileStore: fix OpSequencer::flush error"

This reverts commit c78b29a47d7211a4b8b1585112ac22b8435a82c7.

This commit introduced an error in parallel journaling mode.
OpSequencer::flush is only meant to ensure that the ops have become
readable, not necessarily journalled.

ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph