Merge remote-tracking branch 'remotes/famz/tags/docker-pull-request' into staging

Merge remote-tracking branch 'remotes/famz/tags/docker-pull-request' into staging

# gpg: Signature made Fri 05 Aug 2016 09:58:50 BST
# gpg:                using RSA key 0xCA35624C6A9171C6
# gpg: Good signature from "Fam Zheng <famz@redhat.com>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 5003 7CB7 9706 0F76 F021  AD56 CA35 624C 6A91 71C6

* remotes/famz/tags/docker-pull-request:
  docker: Add "--enable-werror" to configure command line
  docker: Be compatible with older docker

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