LU-13791 sec: enable FS capabilities

LU-13791 sec: enable FS capabilities

FS capabilities are not effective because they are dropped for
non-root users for historical reason: they are used to be enforced
before operations, but now they are checked in MDD layer only (see
mdd_fix_attr()).

Add sanity-sec 51.

Signed-off-by: Lai Siyao <lai.siyao@whamcloud.com>
Change-Id: I3e355f5df5eab5509b5e6774dbc8b82281a34039
Reviewed-on: https://review.whamcloud.com/39399
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Sebastien Buisson <sbuisson@ddn.com>
Reviewed-by: Emoly Liu <emoly@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>