cmd/geth: update the copyright year in the geth command usage (#16537)

cmd/geth/main.go

@@ -146,7 +146,7 @@ func init() {
 	// Initialize the CLI app and start Geth
 	app.Action = geth
 	app.HideVersion = true // we have a command to print the version
-	app.Copyright = "Copyright 2013-2017 The go-ethereum Authors"
+	app.Copyright = "Copyright 2013-2018 The go-ethereum Authors"
 	app.Commands = []cli.Command{
 		// See chaincmd.go:
 		initCommand,

cmd/geth/usage.go

@@ -33,7 +33,7 @@ import (
 var AppHelpTemplate = `NAME:
    {{.App.Name}} - {{.App.Usage}}
 
-   Copyright 2013-2017 The go-ethereum Authors
+   Copyright 2013-2018 The go-ethereum Authors
 
 USAGE:
    {{.App.HelpName}} [options]{{if .App.Commands}} command [command options]{{end}} {{if .App.ArgsUsage}}{{.App.ArgsUsage}}{{else}}[arguments...]{{end}}