functional-tester/tester: remove unused "nopStresser"

Signed-off-by: Gyuho Lee <gyuhox@gmail.com>

tools/functional-tester/tester/stress_nop.go

@@ -1,31 +0,0 @@
-// 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 tester
-
-import "time"
-
-// nopStresser implements Stresser that does nothing
-type nopStresser struct {
-	start time.Time
-	qps   int
-}
-
-func (s *nopStresser) Stress() error { return nil }
-func (s *nopStresser) Pause()        {}
-func (s *nopStresser) Close()        {}
-func (s *nopStresser) ModifiedKeys() int64 {
-	return 0
-}
-func (s *nopStresser) Checker() Checker { return nil }