LU-14430 mdd: rename mti_oa to mdi_oa and friends

LU-14430 mdd: rename mti_oa to mdi_oa and friends

Rename fields in mdd_thread_info to confusion with mdt_thread_info.
The second patch of several to rename all mdd_thread_info fields
to use a more unique field prefix:

  mti_dof->mdi_dof
  mti_dt_rec->mdi_dt_rec
  mti_ent->mdi_ent
  mti_flags->mdi_flags
  mti_hint->mdi_hint
  mti_key->mdi_key
  mti_link_data->mdi_link_data
  mti_name->mdi_name
  mti_oa->mdi_oa
  mti_range->mdi_range
  mti_spec->mdi_spec

The mti_lmv and mti_lrl fields are removed since they are unused.

Lustre-change: https://review.whamcloud.com/43739
Lustre-commit: 9a23a5de12164f9d50db9e602f085bb0c3cc9d8a

Test-Parameters: trivial
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I6fd4b7f26b7e9561d8a8585eaa5438d6093ebbe5
Reviewed-by: Mike Pershin <mpershin@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/46194
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>