clientv3: Move to client/v3 (just file move)

Mechanical:
% git mv clientv3 client/v3
% git mv client/mock client/v3/

client/v3/balancer/utils_test.go

@@ -0,0 +1,34 @@
+// Copyright 2018 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package balancer
+
+import (
+	"reflect"
+	"testing"
+
+	"google.golang.org/grpc/resolver"
+)
+
+func Test_epsToAddrs(t *testing.T) {
+	eps := []string{"https://example.com:2379", "127.0.0.1:2379"}
+	exp := []resolver.Address{
+		{Addr: "example.com:2379", Type: resolver.Backend},
+		{Addr: "127.0.0.1:2379", Type: resolver.Backend},
+	}
+	rs := epsToAddrs(eps...)
+	if !reflect.DeepEqual(rs, exp) {
+		t.Fatalf("expected %v, got %v", exp, rs)
+	}
+}