Merge commit 'block/master' into staging

* commit 'block/master':
  raw-posix: cleanup ioctl methods
  block: add bdrv_probe_device method
  raw-posix: split hdev drivers
  raw-posix: add a raw_open_common helper
  raw-posix: always store open flags
  fix qemu_aio_flush

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>