Only restart services with goreman if they're running

Created by: mrnugget

When running ./dev/start.sh with a modified Procfile, or passing the --only/--except options to it, the list of running services doesn't match the list of binaries the watch command rebuilds.

So what happens is that you modify code, watch re-compiles the binaries and runs into an error:

08:54:27  watch | Building with optimizations disabled (for debugging). Make sure you have at least go1.10 installed.
08:54:32  watch | Rebuilt: symbols precise-code-intel-bundle-manager precise-code-intel-worker
08:54:32  watch | goreman: unknown proc: symbols

Because symbols wasn't running now all three services aren't restarted.

That cost me a lot of time and caused a ton of facepalms... so here's the fix.