upgrade/dumpling-x: do not upgrade client host

If we are running against a mixed cluster for the duration of the upgrade,
we need to make sure we are running the *old* client tests against the
cluster.  Do not upgrade client.0.

Fixes: #7574
Signed-off-by: Sage Weil <sage@inktank.com>
upgrade/dumpling-x/parallel: do all final workloads

Run all of the final workloads in succession instead of in separate tests.
Since we are not concerned about timing in this case, only that the
cluster is functioning at the end, this cuts down our test matrix by a
factor of 4.

Signed-off-by: Sage Weil <sage@inktank.com>
Merge pull request #13 from ceph/wip-upgrade

a few upgrade fixes