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

Block layer patches

# gpg: Signature made Fri 18 Dec 2015 13:41:03 GMT using RSA key ID C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"

* remotes/kevin/tags/for-upstream: (48 commits)
  block/qapi: allow best-effort query
  qemu-img: abort when full_backing_filename not present
  block/qapi: explicitly warn if !has_full_backing_filename
  block/qapi: always report full_backing_filename
  block/qapi: do not redundantly print "actual path"
  qemu-iotests: s390x: fix test 068
  qemu-iotests: s390x: fix test 051
  qemu-iotests: refine common.config
  block: fix bdrv_ioctl called from coroutine
  block: use drained section around bdrv_snapshot_delete
  iotests: Update comments for bdrv_swap() in 094
  block: Remove prototype of bdrv_swap from header
  raw-posix: Make aio=native option binding
  qcow2: insert assert into qcow2_get_specific_info()
  iotests: Extend test 112 for qemu-img amend
  qcow2: Point to amend function in check
  qcow2: Invoke refcount order amendment function
  qcow2: Add function for refcount order amendment
  qcow2: Use intermediate helper CB for amend
  qcow2: Split upgrade/downgrade paths for amend
  ...

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