Fix the builddict and add a basic ci test.

This wires up a run of build-support/bin/publish_docs.sh as part
of the ci suite to at least confirm it runs without raising.

Testing Done:
Now works:
==
./build-support/bin/publish_docs.sh

Travis CI went green here: https://travis-ci.org/pantsbuild/pants/builds/32401953

Bugs closed: 475

Reviewed at https://rbcommons.com/s/twitter/r/873/