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

Block layer patches

# gpg: Signature made Tue 10 Apr 2018 15:53:08 BST
# gpg:                using RSA key 7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream:
  qemu-iotests: update 185 output
  commit/stream: Reset delay_ns
  qemu-iotests: Remove _supported_fmt dmg
  iotests: blacklist bochs and cloop for 205 and 208
  iotests.py: improve verify_image_format helper
  hw/block/pflash_cfi: fix off-by-one error
  iotests.py: support unsupported_fmts in main()

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