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

Block layer patches for 2.11.0-rc2

# gpg: Signature made Tue 21 Nov 2017 15:09:12 GMT
# gpg:                using RSA key 0x7F09B272C88F2FD6
# 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:
  iotests: Fix 176 on 32-bit host
  block: Close a BlockDriverState completely even when bs->drv is NULL
  block: Error out on load_vm with active dirty bitmaps
  block: Add errp to bdrv_all_goto_snapshot()
  block: Add errp to bdrv_snapshot_goto()
  block: Don't request I/O permission with BDRV_O_NO_IO
  block: Don't use BLK_PERM_CONSISTENT_READ for format probing

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