LU-14012 lod: properly initialize lcm in lod_layout_convert()

LU-14012 lod: properly initialize lcm in lod_layout_convert()

In lod_layout_convert() zero out lcm and lcme before constructing the
converted layout.

Lustre-commit: 6f2a1c911f0a326765e6d11f35bb602daf057948
Lustre-change: https://review.whamcloud.com/40153

Signed-off-by: John L. Hammond <jhammond@whamcloud.com>
Change-Id: I40f96d51cb63816a9bfc34217f02ff7c450de974
Reviewed-on: https://review.whamcloud.com/40306
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>