Fix run_envoy_docker.sh 'do_ci.sh ' does not work behind proxy

[249043822]

Description: In @io_bazel_rules_go/go/private/go_repository.bzl, it reads os env HTTP_PROXY and HTTPS_PROXY with upper case:
if "HTTP_PROXY" in ctx.os.environ: fetch_repo_env["HTTP_PROXY"] = ctx.os.environ["HTTP_PROXY"] if "HTTPS_PROXY" in ctx.os.environ: fetch_repo_env["HTTPS_PROXY"] = ctx.os.environ["HTTPS_PROXY"]
if set the container env with lower case, @io_bazel_rules_go/go/private/go_repository.bzl will not fetch the proxy, then the packages which will be downloaded by go_repository failed:
ERROR: /build/tmp/_bazel_bazel/436badd4919a15958fa3800a4e21074a/external/io_bazel_rules_go/proto/BUILD.bazel:21:1: no such package '@org_golang_x_net//context': failed to fetch org_golang_x_net: 2018/07/26 02:33:07 unrecognized import path "golang.org/x/net" and referenced by '@io_bazel_rules_go//proto:go_grpc' ERROR: Analysis of target '//src/envoy:envoy' failed; build aborted: no such package '@org_golang_x_net//context': failed to fetch org_golang_x_net: 2018/07/26 02:33:07 unrecognized import path "golang.org/x/net"
when change to upper case, it works fine, will not need git_hack.sh
Risk Level: CI
Testing:
Docs Changes:
Release Notes:
[Optional Fixes #Issue] #2180
[Optional Deprecated:]

[mattklein123]

Seems reasonable. Thank you!