Remove batcharchive dependency on common.IsDirectory

client/internal/common/utils.go

 // Copyright 2015 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
 package common
 
 import (
         "io"
         "os"
         "runtime"
 
         "github.com/luci/luci-go/common/system/terminal"
 )
 
-// IsDirectory returns true if path is a directory and is accessible.
-func IsDirectory(path string) bool {
-        fileInfo, err := os.Stat(path)
-        return err == nil && fileInfo.IsDir()
-}
-
 // IsWindows returns True when running on the best OS there is.
 func IsWindows() bool {
         return runtime.GOOS == "windows"
 }
 
 // IsTerminal returns true if the specified io.Writer is a terminal.
 func IsTerminal(out io.Writer) bool {
         f, ok := out.(*os.File)
         if !ok {
                 return false
         }
         return terminal.IsTerminal(int(f.Fd()))
 }