Merge remote-tracking branch 'remotes/maxreitz/tags/pull-block-2020-06-24' into staging

Block patches:
- Two iotest fixes

# gpg: Signature made Wed 24 Jun 2020 09:00:51 BST
# gpg:                using RSA key 91BEB60A30DB3E8857D11829F407DB0061D5CF40
# gpg:                issuer "mreitz@redhat.com"
# gpg: Good signature from "Max Reitz <mreitz@redhat.com>" [full]
# Primary key fingerprint: 91BE B60A 30DB 3E88 57D1  1829 F407 DB00 61D5 CF40

* remotes/maxreitz/tags/pull-block-2020-06-24:
  iotests: don't test qcow2.py inside 291
  iotests: Fix 051 output after qdev_init_nofail() removal

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>