housecleaning

I'm cleaning house. Please help me audit this list of what is left. /cc @xiangli-cmu @unihorn 

- [ ] third_party/.../go-log -> go-systemd && third_party//bitbucket.org/kardianos/osext
- [ ] third_party/.../go-etcd -- xiang is working on it!
- [ ] error/ -> ./discovery -- xiang is working on it!
- [ ] http/ -- needs review (does CORS stuff in for main)
- [ ] bench/ -- needs review
- [ ] fixtures/ -- needs review
- [ ] config/ -- we should be able to move this into etcd/
- [ ] pkg/ -- needs review? what is