Merge pull request #5046 from ceph/wip-12109-hammer

librbd: new QA client upgrade tests

Reviewed-by: Loic Dachary <ldachary@redhat.com>

diff --cc src/test/librbd/test_ImageWatcher.cc
Simple merge

diff --cc src/test/librbd/test_internal.cc
Simple merge

diff --cc src/test/librbd/test_librbd.cc
Simple merge