Tweaking the Golang binaries build.

- Replace go get with go install since that's the new blessed way of
  doing things (IIUC go get is going to be deprecated eventually). Don't
change for reg since that fails to build with go install.
- Ignore failure to build keybase and kbfs. It's some Golang dependency
  issue and right now it seems like we're moving away from Keybase
altogether in work so I'm not going to invest time trying to fix this.