LU-1064 mds: journal locking issue was fixed

LU-1064 mds: journal locking issue was fixed

During the downgrade procedure locking during
lma data removal is observed. The patch fix
this issue by moving the lma remove under the
mutex.

Reviewed-by: Vitaly Fertman <vfertman@xyratex.com>
Reviewed-by: Andrew Perepechko <aperepechko@xyratex.com>
Xyratex-bug-id: MRP-251

Signed-off-by: Iurii Golovach <Iurii_Golovach@xyratex.com>
Change-Id: I01e7bda03e3b0dfae92b7e03672c56b23a73989d
Reviewed-on: http://review.whamcloud.com/2077
Tested-by: Hudson
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Keith Mannthey <kemannthey@gmail.com>