LU-4703 mdd: do not skip xattr sanity check for all cases

LU-4703 mdd: do not skip xattr sanity check for all cases

xattr sanity check should be done at all times.
Otherwise we are risking letting a non root user setting
access acl on any file.

Signed-off-by: Li Dongyang <dongyang.li@anu.edu.au>
Change-Id: I5f44d38f2589f0758548d8ccae5efef27205f0a0
Reviewed-on: http://review.whamcloud.com/9469
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>