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

Block patches for 2.3

# gpg: Signature made Fri 23 Jan 2015 17:53:06 GMT using RSA key ID C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"

* remotes/kevin/tags/for-upstream:
  iotests: Lower 064's memory usage
  block: vhdx - force FileOffsetMB field to '0' for certain block states
  block: update string sizes for filename,backing_file,exact_filename
  block: mirror - change string allocation to 2-bytes
  block: remove unused variable in bdrv_commit
  block: qapi - move string allocation from stack to the heap
  block: vmdk - move string allocations from stack to the heap
  block: vmdk - make ret variable usage clear
  iotests: Add tests for more corruption cases
  qcow2: Add two more unalignment checks
  virtio-blk: Use blk_aio_ioctl
  virtio-blk: Pass req to virtio_blk_handle_scsi_req

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