Merge remote-tracking branch 'remotes/famz/tags/pull-docker-20160608' into staging

Merge remote-tracking branch 'remotes/famz/tags/pull-docker-20160608' into staging

Docker testing fixes by Paolo.

# gpg: Signature made Wed 08 Jun 2016 08:20:54 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/pull-docker-20160608:
  tests/docker: build all targets in test-clang
  tests/docker: support travis test with fedora image
  tests/docker: remove unused feature "ccache"
  tests/docker: fix test-mingw
  tests/docker: make test-full build all targets, not none
  tests/docker: fix make-archive-maybe

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