erasure-code: add jerasure k=3 m=1 workload

It validates that http://tracker.ceph.com/issues/9209 is fixed.

Signed-off-by: Loic Dachary <loic-201408@dachary.org>
Merge pull request #107 from dachary/wip-9209-ec-workload

erasure-code: add jerasure k=3 m=1 workload