Cleanup math/rand package usage

Kubernetes-commit: 4ce1fb7d40beb9010e56d60792c4da25e8d86ed0

util/workqueue/delaying_queue_test.go

@@ -216,15 +216,13 @@ func TestCopyShifting(t *testing.T) {
 }
 
 func BenchmarkDelayingQueue_AddAfter(b *testing.B) {
-	r := rand.New(rand.NewSource(time.Now().Unix()))
-
 	fakeClock := clock.NewFakeClock(time.Now())
 	q := newDelayingQueue(fakeClock, "")
 
 	// Add items
 	for n := 0; n < b.N; n++ {
 		data := fmt.Sprintf("%d", n)
-		q.AddAfter(data, time.Duration(r.Int63n(int64(10*time.Minute))))
+		q.AddAfter(data, time.Duration(rand.Int63n(int64(10*time.Minute))))
 	}
 
 	// Exercise item removal as well

util/workqueue/main_test.go

@@ -0,0 +1,29 @@
+/*
+Copyright 2018 The Kubernetes 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 workqueue
+
+import (
+	"math/rand"
+	"os"
+	"testing"
+	"time"
+)
+
+func TestMain(m *testing.M) {
+	rand.Seed(time.Now().UnixNano())
+	os.Exit(m.Run())
+}