add prune and remove unused packages

vendor/google.golang.org/grpc/internal/syscall/syscall_nonlinux.go

@@ -1,47 +0,0 @@
-// +build !linux appengine !go1.7
-
-/*
- *
- * Copyright 2018 gRPC 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 syscall
-
-import "google.golang.org/grpc/grpclog"
-
-func init() {
-	grpclog.Info("CPU time info is unavailable on non-linux or appengine environment.")
-}
-
-// GetCPUTime returns the how much CPU time has passed since the start of this process.
-// It always returns 0 under non-linux or appengine environment.
-func GetCPUTime() int64 {
-	return 0
-}
-
-// Rusage is an empty struct under non-linux or appengine environment.
-type Rusage struct{}
-
-// GetRusage is a no-op function under non-linux or appengine environment.
-func GetRusage() (rusage *Rusage) {
-	return nil
-}
-
-// CPUTimeDiff returns the differences of user CPU time and system CPU time used
-// between two Rusage structs. It a no-op function for non-linux or appengine environment.
-func CPUTimeDiff(first *Rusage, latest *Rusage) (float64, float64) {
-	return 0, 0
-}