Merge remote-tracking branch 'remotes/stefanha/tags/block-pull-request' into staging

# gpg: Signature made Fri 09 Mar 2018 13:19:02 GMT
# gpg:                using RSA key 9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* remotes/stefanha/tags/block-pull-request:
  vl: introduce vm_shutdown()
  virtio-scsi: fix race between .ioeventfd_stop() and vq handler
  virtio-blk: fix race between .ioeventfd_stop() and vq handler
  block: add aio_wait_bh_oneshot()
  virtio-blk: dataplane: Don't batch notifications if EVENT_IDX is present
  README: Fix typo 'git-publish'
  block: Fix qemu crash when using scsi-block

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