LU-4992 llite: validate names

LU-4992 llite: validate names

In ll_prep_md_op_data() validate names according to the same formula
used in mdd_name_check(). Add mdc_pack_name() to validate the name
actually packed in the request.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: Ib56951ab7be7196c79b94dc1848757b4bdf30ce6
Reviewed-on: http://review.whamcloud.com/10198
Tested-by: Jenkins
Reviewed-by: wangdi <di.wang@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>