search broken on internal Hub

[afeld]

Works fine on https://18f.gsa.gov/hub/.

/cc @mbland

[mbland]

After comparing git checksums, and search file md5 sums, I tried to download the live index. Of course I found:

When I added the experimental /search endpoint for 18F/lunr-server, its Nginx location directive intercepted /search-index.json. Just added a dedicated location rule for /search-index.json explicitly and we're back in business.

I did notice that the https://hub.18f.gov/hub/ build was breaking due to line 104 in ./go getting an empty argument for args; I'll send a PR for that now.