discovery: add ability to proxy discovery requests
store: remove unused code
Merge pull request #1311 from jonboulle/remove_ttl

store: remove unused code
Merge pull request #909 from jonboulle/proxy

Support corporate proxy via env var
raft: remove unused compactThreshold
Merge pull request #1314 from jonboulle/raft_tests

raft: remove unused compactThreshold
etcdserver: fix data race in retrieving self stats