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: NPeter Maydell <peter.maydell@linaro.org>

tests/docker/Makefile.include

@@ -107,9 +107,8 @@ docker-run-%: docker-qemu-src
 	fi
 	$(if $(filter $(TESTS),$(CMD)),$(if $(filter $(IMAGES),$(IMAGE)), \
 		$(call quiet-command,\
-			if $(SRC_PATH)/tests/docker/docker.py images \
-				--format={{.Repository}}:{{.Tag}} | \
-					grep -qx qemu:$(IMAGE); then \
+			if $(SRC_PATH)/tests/docker/docker.py images | \
+				awk '$$1=="qemu" && $$2=="$(IMAGE)"{found=1} END{exit(!found)}'; then \
 				$(SRC_PATH)/tests/docker/docker.py run $(if $V,,--rm) \
 				-t \
 				$(if $(DEBUG),-i,--net=none) \

tests/docker/common.rc

@@ -24,6 +24,7 @@ requires()
 build_qemu()
 {
     $QEMU_SRC/configure \
+        --enable-werror \
         ${TARGET_LIST:+"--target-list=${TARGET_LIST}"} \
         --prefix="$PWD/install" \
         $EXTRA_CONFIGURE_OPTS \