LU-14575 ofd: suppress errors on missing parent FID

LU-14575 ofd: suppress errors on missing parent FID

In ofd_access(), if the parent FID is zero then skip adding an entry
to the OFD access log.

Signed-off-by: John L. Hammond <jhammond@whamcloud.com>
Change-Id: Ib518dc1f181a820d99021dd58ab548916e16f29d
Reviewed-on: https://review.whamcloud.com/43184
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>