qa: do not create erasure pools yet

comment out erasure pool related tests when an OSD is involved because
it does not work yet. See http://tracker.ceph.com/issues/7360.

Signed-off-by: Loic Dachary <loic@dachary.org>
Merge pull request #1249 from dachary/wip-qa-erasure-test

qa: do not create erasure pools yet