Gitserver GC logic potentially not working

Created by: attfarhan

• Sourcegraph version: Sourcegraph.com

The kubernetes/kubernetes repo was loading extremely slowly on sourcegraph.com. Stephen tried running git gc on the repo and it took a very long time, enumerating 140k objects in 3 minutes. He fixed the slowness by re-cloning the repo.

See original slack thread here: https://sourcegraph.slack.com/archives/CHPC7UX16/p1568075963065700