ec-rados-default is not fit for dumpling parallel upgrade

Because it may race with the upgrade and end up being unable to perform.

http://tracker.ceph.com/issues/9608 Fixes: #9608

Signed-off-by: Loic Dachary <loic-201408@dachary.org>
(cherry picked from commit b77ef02bc5ca623d2c5577c2caafcf3720ddd2ec)
Merge pull request #152 from dachary/wip-9608-ec-default-parallel-giant

ec-rados-default is not fit for dumpling parallel upgrade