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

Block layer patches for 2.11.0-rc2

# gpg: Signature made Fri 17 Nov 2017 17:58:36 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: (25 commits)
  iotests: Make 087 pass without AIO enabled
  block: Make bdrv_next() keep strong references
  qcow2: Fix overly broad madvise()
  qcow2: Refuse to get unaligned offsets from cache
  qcow2: Add bounds check to get_refblock_offset()
  block: Guard against NULL bs->drv
  qcow2: Unaligned zero cluster in handle_alloc()
  qcow2: check_errors are fatal
  qcow2: reject unaligned offsets in write compressed
  iotests: Add test for failing qemu-img commit
  tests: Add check-qobject for equality tests
  iotests: Add test for non-string option reopening
  block: qobject_is_equal() in bdrv_reopen_prepare()
  qapi: Add qobject_is_equal()
  qapi/qlist: Add qlist_append_null() macro
  qapi/qnull: Add own header
  qcow2: fix image corruption on commit with persistent bitmap
  iotests: test clearing unknown autoclear_features by qcow2
  block: Fix permissions in image activation
  qcow2: fix image corruption after committing qcow2 image into base
  ...

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