raft: remove sync

We don't need SyncNode. We only care about things that have made it
through the store. We can do this there.

raft2/sync.go

@@ -1,41 +0,0 @@
-package raft
-
-import (
-	"code.google.com/p/go.net/context"
-	"github.com/coreos/etcd/wait"
-)
-
-type SyncNode struct {
-	n *Node
-	w wait.WaitList
-}
-
-func NewSyncNode(n *Node) *SyncNode { panic("not implemented") }
-
-type waitResp struct {
-	e   Entry
-	err error
-}
-
-func (n *SyncNode) Propose(ctx context.Context, id int64, data []byte) (Entry, error) {
-	ch := n.w.Register(id)
-	n.n.Propose(id, data)
-	select {
-	case x := <-ch:
-		wr := x.(waitResp)
-		return wr.e, wr.err
-	case <-ctx.Done():
-		n.w.Trigger(id, nil) // GC the Wait
-		return Entry{}, ctx.Err()
-	}
-}
-
-func (n *SyncNode) ReadState() (State, []Entry, []Message, error) {
-	st, ents, msgs, err := n.n.ReadState()
-	for _, e := range ents {
-		if e.Index >= st.CommitIndex {
-			n.w.Trigger(e.Id, waitResp{e: e, err: nil})
-		}
-	}
-	return st, ents, msgs, err
-}