in lus_mdt_stat_by_fid, use FID_NOBRACE_LEN to store the fid
in lus_mdt_stat_by_fid, use FID_NOBRACE_LEN to store the fid

If it's formated as DFID_NOBRACE, the string is only FID_NOBRACE_LEN +
1 bytes long.

fzago-cray/liblustre,fzago-cray/liblustre