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

# gpg: Signature made Mon 24 Apr 2017 20:18:05 BST
# gpg:                using RSA key 0xBDBE7B27C0DE3057
# gpg: Good signature from "Jeffrey Cody <jcody@redhat.com>"
# gpg:                 aka "Jeffrey Cody <jeff@codyprime.org>"
# gpg:                 aka "Jeffrey Cody <codyprime@gmail.com>"
# Primary key fingerprint: 9957 4B4D 3474 90E7 9D98  D624 BDBE 7B27 C0DE 3057

* remotes/cody/tags/block-pull-request:
  qemu-iotests: _cleanup_qemu must be called on exit
  block/rbd: Add support for reopen()
  block/rbd - update variable names to more apt names
  block: use bdrv_can_set_read_only() during reopen
  block: introduce bdrv_can_set_read_only()
  block: code movement
  block: honor BDRV_O_ALLOW_RDWR when clearing bs->read_only
  block: do not set BDS read_only if copy_on_read enabled
  block: add bdrv_set_read_only() helper function
  qemu-iotests: exclude vxhs from image creation via protocol
  block/vxhs.c: Add qemu-iotests for new block device type "vxhs"
  block/vxhs.c: Add support for a new block device type called "vxhs"

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