directory structure change to work with glide

glide has its own requirements. My previous workaround caused me some
code checkin errors. Need to fix this.

weed/util/file_util.go

@@ -0,0 +1,38 @@
+package util
+
+import (
+	"bufio"
+	"errors"
+	"os"
+
+	"github.com/chrislusf/seaweedfs/weed/glog"
+)
+
+func TestFolderWritable(folder string) (err error) {
+	fileInfo, err := os.Stat(folder)
+	if err != nil {
+		return err
+	}
+	if !fileInfo.IsDir() {
+		return errors.New("Not a valid folder!")
+	}
+	perm := fileInfo.Mode().Perm()
+	glog.V(0).Infoln("Folder", folder, "Permission:", perm)
+	if 0200&perm != 0 {
+		return nil
+	}
+	return errors.New("Not writable!")
+}
+
+func Readln(r *bufio.Reader) ([]byte, error) {
+	var (
+		isPrefix = true
+		err      error
+		line, ln []byte
+	)
+	for isPrefix && err == nil {
+		line, isPrefix, err = r.ReadLine()
+		ln = append(ln, line...)
+	}
+	return ln, err
+}