proxy: The priority does not take effect when picking the remote object.

[SimFG]

when finding best priority class, we get the weighted or unweighted array. If the weighted is valid, we will get a remote according to the random num and weight. If the unweighted is valid, get a remote according to the pickCount and the priority attribute isn't used. But I don't know how to use the priority to get a remote.
Putting the element whose priority is 1 at the end of the array as follows, it will fail.

the pick function detail:

etcd/server/proxy/tcpproxy/userspace.go

Lines 118 to 173 in 33ba538

	func (tp *TCPProxy) pick() *remote {
	var weighted []*remote
	var unweighted []*remote
	bestPr := uint16(65535)
	w := 0
	// find best priority class
	for _, r := range tp.remotes {
	switch {
	case !r.isActive():
	case r.srv.Priority < bestPr:
	bestPr = r.srv.Priority
	w = 0
	weighted = nil
	unweighted = nil
	fallthrough
	case r.srv.Priority == bestPr:
	if r.srv.Weight > 0 {
	weighted = append(weighted, r)
	w += int(r.srv.Weight)
	} else {
	unweighted = append(unweighted, r)
	}
	}
	}
	if weighted != nil {
	if len(unweighted) > 0 && rand.Intn(100) == 1 {
	// In the presence of records containing weights greater
	// than 0, records with weight 0 should have a very small
	// chance of being selected.
	r := unweighted[tp.pickCount%len(unweighted)]
	tp.pickCount++
	return r
	}
	// choose a uniform random number between 0 and the sum computed
	// (inclusive), and select the RR whose running sum value is the
	// first in the selected order
	choose := rand.Intn(w)
	for i := 0; i < len(weighted); i++ {
	choose -= int(weighted[i].srv.Weight)
	if choose <= 0 {
	return weighted[i]
	}
	}
	}
	if unweighted != nil {
	for i := 0; i < len(tp.remotes); i++ {
	picked := tp.remotes[tp.pickCount%len(tp.remotes)]
	tp.pickCount++
	if picked.isActive() {
	return picked
	}
	}
	}
	return nil
	}