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.

Signed-off-by: Li Xi <lixi@ddn.com>
Change-Id: I1e5c44674f2e22ecbe29a589a219bed52d037b9b
Reviewed-on: http://review.whamcloud.com/9473
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>