Makefile: remove passing proxy env-vars

Docker 17.07 and up allow the CLI to be configured to set default proxy
env-vars to be used (both as build-arg and as env for docker run), see
docker/cli#93, so setting these here should be redundant. If someone
needs these env-vars set, they should be configured in the cli's
`~/.docker/config.json` instead.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

Makefile

@@ -82,12 +82,6 @@ DOCKER_ENVS := \
 	-e VALIDATE_REPO \
 	-e VALIDATE_BRANCH \
 	-e VALIDATE_ORIGIN_BRANCH \
-	-e HTTP_PROXY \
-	-e HTTPS_PROXY \
-	-e NO_PROXY \
-	-e http_proxy \
-	-e https_proxy \
-	-e no_proxy \
 	-e VERSION \
 	-e PLATFORM \
 	-e DEFAULT_PRODUCT_LICENSE \