Merge remote-tracking branch 'kwolf/for-anthony' into staging

* kwolf/for-anthony: (27 commits)
  qemu-img: fix segment fault when the image format is qed
  qemu-io: fix segment fault when the image format is qed
  qemu-tool: revert cpu_get_clock() abort(3)
  qemu-iotests: Test rebase with short backing file
  qemu-iotests: 026: Reduce output changes for cache=none qcow2
  qemu-iotests: Filter out DOS line endings
  test: add image streaming tests
  qemu-iotests: add iotests Python module
  qemu-iotests: export TEST_DIR for non-bash tests
  QMP: Add qmp command for blockdev-group-snapshot-sync
  qapi: Introduce blockdev-group-snapshot-sync command
  qcow2: Reject too large header extensions
  qcow2: Fix offset in qcow2_read_extensions
  block: drop aio_multiwrite in BlockDriver
  block: remove unused fields in BlockDriverState
  qcow2: Fix build with DEBUG_EXT enabled
  ide: fail I/O to empty disk
  fdc: DIR (Digital Input Register) should return status of current drive...
  fdc: fix seek command, which shouldn't check tracks
  fdc: check if media rate is correct before doing any transfer
  ...