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

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

Block patches

# gpg: Signature made Mon 19 May 2014 15:21:14 BST using RSA key ID C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"

* remotes/kevin/tags/for-upstream: (22 commits)
  block: optimize zero writes with bdrv_write_zeroes
  blockdev: add a function to parse enum ids from strings
  util: add qemu_iovec_is_zero
  qcow1: Stricter backing file length check
  qcow1: Validate image size (CVE-2014-0223)
  qcow1: Validate L2 table size (CVE-2014-0222)
  qcow1: Check maximum cluster size
  qcow1: Make padding in the header explicit
  curl: Add usage documentation
  curl: Add sslverify option
  curl: Remove broken parsing of options from url
  curl: Fix build when curl_multi_socket_action isn't available
  qemu-iotests: Fix blkdebug in VM drive in 030
  qemu-iotests: Fix core dump suppression in test 039
  iotests: Add test for the JSON protocol
  block: Allow JSON filenames
  check-qdict: Add test for qdict_join()
  qdict: Add qdict_join()
  block: add test for vhdx image created by Disk2VHD
  block: vhdx - account for identical header sections
  ...

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