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

Block layer patches:

- Add blockdev-create job
- qcow2: Silence Coverity false positive

# gpg: Signature made Wed 30 May 2018 16:55:31 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:
  block/create: Mark blockdev-create stable
  qemu-iotests: Rewrite 213 for blockdev-create job
  qemu-iotests: Rewrite 212 for blockdev-create job
  qemu-iotests: Rewrite 211 for blockdev-create job
  qemu-iotests: Rewrite 210 for blockdev-create job
  qemu-iotests: Rewrite 207 for blockdev-create job
  qemu-iotests: Rewrite 206 for blockdev-create job
  qemu-iotests: iotests.py helper for non-file protocols
  qemu-iotests: Add VM.run_job()
  qemu-iotests: Add iotests.img_info_log()
  qemu-iotests: Add VM.qmp_log()
  qemu-iotests: Add VM.get_qmp_events_filtered()
  block/create: Make x-blockdev-create a job
  job: Add error message for failing jobs
  vhdx: Fix vhdx_co_create() return value
  vdi: Fix vdi_co_do_create() return value
  qcow2: Fix Coverity warning when calculating the refcount cache size

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