filestore: fix journal locking on trailing mode
filestore: fix journal locking on trailing mode

We're already holding journal_lock due to the surrounding
op_submit_{start,finish}.

Signed-off-by: Sage Weil <6dd34506bbd5e58221bbb3e4732d97c91f02277b@newdream.net>

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