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

# By Stefan Hajnoczi (11) and others
# Via Kevin Wolf
* kwolf/for-anthony:
  cmd646: fix build when DEBUG_IDE is enabled.
  block: change default of .has_zero_init to 0
  vpc: Implement .bdrv_has_zero_init
  vmdk: remove wrong calculation of relative path
  gluster: Return bdrv_has_zero_init = 0
  block/ssh: Set bdrv_has_zero_init according to the file type.
  block: Make BlockJobTypes const
  qemu-iotests: add 055 drive-backup test case
  qemu-iotests: extract wait_until_completed() into iotests.py
  blockdev: add Abort transaction
  blockdev: add DriveBackup transaction
  blockdev: allow BdrvActionOps->commit() to be NULL
  blockdev: rename BlkTransactionStates to singular
  block: add drive-backup QMP command
  blockdev: use bdrv_getlength() in qmp_drive_mirror()
  blockdev: drop redundant proto_drv check
  block: add basic backup support to block driver
  block: add bdrv_add_before_write_notifier()
  notify: add NotiferWithReturn so notifier list can abort
  raw-posix: Fix /dev/cdrom magic on OS X

Message-id: 1372429509-29642-1-git-send-email-kwolf@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>