EX-7601 ofd: add chunk rounding to write

EX-7601 ofd: add chunk rounding to write

For compressed files, we need to round all niobufs to
chunk size in the write process, so we have buffers for
reading in and rewriting the complete chunks.

dt_bufs_get sets up the local niobuf for the write, so we
round before calling it.

Note this breaks writing to compressed files, which is not
fixed until a few patches later.  For this reason, we
disable the compression tests.  They will be reenabled
shortly - similar to how we handled the read series.

Signed-off-by: Patrick Farrell <pfarrell@whamcloud.com>
Change-Id: I413aaba9866dd7d6c4463fa620eadf1423379ba1
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/52963
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Artem Blagodarenko <ablagodarenko@ddn.com>