LU-3467 seq: unified SEQ handler

LU-3467 seq: unified SEQ handler

move SEQ handler from MDT to the FID module so it can
be used from any target.

Signed-off-by: Mikhail Pershin <mike.pershin@intel.com>
Change-Id: I1777eddd748486aab275e4440f96685bed0b104a
Reviewed-on: http://review.whamcloud.com/6765
Tested-by: Hudson
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: wangdi <di.wang@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>