Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Patches for 5.2.0-rc3:

- qcow2: Fix corruption on write_zeroes with MAY_UNMAP

# gpg: Signature made Tue 24 Nov 2020 14:23:36 GMT
# gpg:                using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6
# gpg:                issuer "kwolf@redhat.com"
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream:
  qcow2: Fix corruption on write_zeroes with MAY_UNMAP

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