Make protobuf build

This includes the following:
  - Setting up dependencies protobuf needs
  - A few hacks to make protobuf work with our version of Bazel (going
    to upgrade soon...)
  - A few tweaks to make protobuf be happy in third_party
  - Commenting out a few things we don't care about that didn't want to
    work

Tested with -c fastbuild for all 3 toolchains.

Change-Id: I02c50cd7e82e509bd7973f2e7cecf9b7d183783e
diff --git a/third_party/protobuf/util/python/BUILD b/third_party/protobuf/util/python/BUILD
index 358c381..073ea63 100644
--- a/third_party/protobuf/util/python/BUILD
+++ b/third_party/protobuf/util/python/BUILD
@@ -1,3 +1,5 @@
+licenses(["notice"])
+
 # This is a placeholder for python headers. Projects needing to use
 # fast cpp protos in protobuf's python interface should build with
 # --define=use_fast_cpp_protos=true, and in addition, provide