erasure-code: verify that rados put enforces alignment

http://tracker.ceph.com/issues/8622 refs: #8622

Signed-off-by: Loic Dachary <loic@dachary.org>
Merge pull request #1987 from dachary/wip-8622-rados-alignment

erasure-code: verify that rados put enforces alignment

Reviewed-by: Lluis Pamies-Juarez <lluis@pamies.cat>