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

Block layer patches:

- scsi-cd: Fix inserting read-only media in empty drive
- block/copy-on-read: Fix permissions for inactive node
- Test case fixes

# gpg: Signature made Tue 30 Jul 2019 12:21:48 BST
# gpg:                using RSA key 7F09B272C88F2FD6
# 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:
  scsi-cd: Fix inserting read-only media in empty drive
  block/copy-on-read: Fix permissions for inactive node
  Fixes: add read-zeroes to 051.out
  tests/multiboot: Fix load address of test kernels

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