Merge remote-tracking branch 'remotes/cody/tags/block-pull-request' into staging

Merge remote-tracking branch 'remotes/cody/tags/block-pull-request' into staging

# gpg: Signature made Tue 21 Feb 2017 15:40:05 GMT
# gpg:                using RSA key 0xBDBE7B27C0DE3057
# gpg: Good signature from "Jeffrey Cody <jcody@redhat.com>"
# gpg:                 aka "Jeffrey Cody <jeff@codyprime.org>"
# gpg:                 aka "Jeffrey Cody <codyprime@gmail.com>"
# Primary key fingerprint: 9957 4B4D 3474 90E7 9D98  D624 BDBE 7B27 C0DE 3057

* remotes/cody/tags/block-pull-request:
  qemu-options: Fix broken sheepdog URL
  mirror: do not increase offset during initial zero_or_discard phase
  QAPI: Fix blockdev-add example documentation
  iscsi: Add blockdev-add support
  iscsi: Add timeout option
  iscsi: Add header-digest option
  iscsi: Add initiator-name option
  iscsi: Handle -iscsi user/password in bdrv_parse_filename()
  iscsi: Split URL into individual options

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