remove some old useless code

util/mapreduce/mapreduce.go

-package mapreduce
-
-func MapReduce(mapper func(interface{}, chan interface{}),
-	reducer func(chan interface{}, chan interface{}),
-	input chan interface{},
-	pool_size int) interface{} {
-	reduce_input := make(chan interface{})
-	reduce_output := make(chan interface{})
-	worker_output := make(chan chan interface{}, pool_size)
-	go reducer(reduce_input, reduce_output)
-	go func() {
-		for worker_chan := range worker_output {
-			reduce_input <- <-worker_chan
-		}
-		close(reduce_input)
-	}()
-	go func() {
-		for item := range input {
-			my_chan := make(chan interface{})
-			go mapper(item, my_chan)
-			worker_output <- my_chan
-		}
-		close(worker_output)
-	}()
-	return <-reduce_output
-}

util/tempfile.go

-package util
-
-import (
-	"crypto/rand"
-	"encoding/hex"
-	"fmt"
-	"os"
-	"path/filepath"
-	"time"
-)
-
-var (
-	tmpdir = os.TempDir()
-)
-
-func TempName(prefix, suffix string) string {
-	buf := make([]byte, 4)
-	rand.Read(buf)
-	return filepath.Join(
-		tmpdir,
-		fmt.Sprintf(
-			"%s%d.%d.%s%s",
-			prefix,
-			os.Getpid(),
-			time.Now().Unix(),
-			hex.EncodeToString(buf),
-			suffix))
-
-}
-
-func TempFile(prefix, suffix string) (*os.File, error) {
-	return os.Create(TempName(prefix, suffix))
-}