rgw: increase the number of OSDs for erasure coded pools

So that there never is less than 4 osd which is the minimum when trying
erasure coded workloads that only work with 4 osd.

http://tracker.ceph.com/issues/9298 Fixes: #9298

Signed-off-by: Loic Dachary <loic-201408@dachary.org>
Merge pull request #122 from ceph/wip-9357-wusui

Create dumpling-giant-x stress-split upgrade suite
Merge pull request #116 from dachary/wip-9298-rgw-ec-starvation

rgw: increase the number of OSDs for erasure coded pools
tasks: add watch_notify_same_primary

Reproduces: #9220
Signed-off-by: Samuel Just <sam.just@inktank.com>
Merge pull request #130 from ceph/wip-9220

tasks: add watch_notify_same_primary

Reviewed-by: Sage Weil <sage@redhat.com>
Use same upgrade-test as firefly.
The changes for firefly upgrade tests apply to giant as well.