LU-10829 utils: don't print lmm_stripe_offset for DoM layout

LU-10829 utils: don't print lmm_stripe_offset for DoM layout

Running "lfs getstripe" on a DoM file prints out a non-zero value for
"lmm_stripe_offset:" on the 'mdt' component, even though this doesn't
make any sense.  Also, it prints an "lmm_objects:" header for the
component, even though it does not have any objects allocated to it.

  lcm_layout_gen:    4
  lcm_mirror_count:  1
  lcm_entry_count:   3
    lcme_id:             1
    lcme_mirror_id:      0
    lcme_flags:          init
    lcme_extent.e_start: 0
    lcme_extent.e_end:   1048576
      lmm_stripe_count:  0
      lmm_stripe_size:   1048576
      lmm_pattern:       mdt
      lmm_layout_gen:    0
      lmm_stripe_offset: 2
      lmm_objects:

Always print '0' for lmm_stripe_offset of DoM components, and don't
print "lmm_objects:" for these components at all.

Test-Parameters: trivial testlist=sanity-dom,sanity-flr
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Change-Id: I5430ff74d26ad2acd51d07ec23810cc9033ebbe5
Reviewed-on: https://review.whamcloud.com/31702
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>