erasure-code: fix bugous ec-rados-default.yaml in some suites

The ec-rados-default.yaml was linked to suites as if it was a task
although it is a workload intended for parallel upgrade tests.

The ec-rados-plugin=jerasure-k=2-m=1.yaml task is defined and used
instead, where relevant.

Signed-off-by: Loic Dachary <loic-201408@dachary.org>