.ensure-syscall-test need to build an image, we have
to add http_proxy and https_proxy to make it work.
Inseted of adding http_proxy and https_proxy env to the Dockerfile,
adding a DOCKER_BUILD_ARGS env to pass the build-arg is much more
elegant.
Signed-off-by: Lei Jitang <leijitang@huawei.com>
Upstream-commit: 3ff67256132febad4d039845e97db2ad4d55025d
Component: engine