src-expose: avoid git update-server-info in request path
Created by: keegancsmith
We now only run git update-server-info if a repository has not been configured.
This change exposed a bug in our hook setting being incorrect. This wasn't visible before since we would always run update-server-info when listing repos.
Note: This use of protocol v0 has other issues. I will be working on using git protocol v2 soon to make this more robust and performant.