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>
Change-Id: If6bda8ec6b3d91f31bef812acb9f9f636ed56291
Reviewed-on: http://review.whamcloud.com/9514
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Emoly Liu <emoly.liu@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>