LU-4704 acl: fix permission problem of setfacl

LU-4704 acl: fix permission problem of setfacl

Setxattr does not check the permission when setting ACL xattrs. This
will cause security problem because any user can walk around
permission checking by changing ACL rules.

Lustre-commit: 42f504ecada81d7a2a8e2244f345e8dbf73fd157
Lustre-change: http://review.whamcloud.com/9473

Signed-off-by: Li Xi <lixi@ddn.com>
Signed-off-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Emoly Liu <emoly.liu@intel.com>
Change-Id: I5844c5b654afd70fb3b5ee91c024736b377124b0
Reviewed-on: http://review.whamcloud.com/9559
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>