LU-10290 tests: properly set fileset with combined MGT/MDT

LU-10290 tests: properly set fileset with combined MGT/MDT

We need to make sure MDS receives updated fileset info from MGS.
In case of combined MGT/MDT, directly setting fileset on the node
will mask llog-based info retrieval mechanism.
This patch also removes sanity-sec test_27 from ALWAYS_EXCEPT.

Test-Parameters: trivial testlist=sanity-sec,sanity-sec,sanity-sec,sanity-sec
Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
Change-Id: I7f25f03a213833f15d082a871ac6368a0e11aa82
Reviewed-on: https://review.whamcloud.com/30293
Tested-by: Jenkins
Reviewed-by: James Nunez <james.a.nunez@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Reviewed-by: Stephan Thiell <sthiell@stanford.edu>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>