Merge remote-tracking branch 'stefanha/block' into staging

# By Fam Zheng (2) and Stefan Hajnoczi (1)
# Via Stefan Hajnoczi
* stefanha/block:
  block: fix bdrv_flush() ordering in bdrv_close()
  curl: refuse to open URL from HTTP server without range support
  vmdk: Implement .bdrv_has_zero_init

Message-id: 1373023972-3587-1-git-send-email-stefanha@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>