Adds named return value to copyDiskImage()

Docker-DCO-1.1-Signed-off-by: Isaac Boehman <admin@yacn.pw> (github: yacn)

Author: Isaac Boehman

vbm.go

@@ -2,8 +2,8 @@ package main
 
 import (
 	"bytes"
+	"io"
 	"os"
-  "io"
 	"path/filepath"
 
 	vbx "github.com/boot2docker/boot2docker-cli/virtualbox"
@@ -68,30 +68,30 @@ func getHostOnlyNetworkInterface() (string, error) {
 }
 
 // Copy disk image from given source path to destination
-func copyDiskImage(dst, src string) error {
-  // Open source disk image
-  srcImg, err := os.Open(src)
-  if err != nil {
-    return err
-  }
-  closeSrcImg := func() {
-    if ee := srcImg.Close(); ee != nil {
-      err = ee
-    }
-  }
-  defer closeSrcImg()
-  dstImg, err := os.Create(dst)
-  if err != nil {
-    return err
-  }
-  closeDstImg := func() {
-    if ee := dstImg.Close(); ee != nil {
-      err = ee
-    }
-  }
-  defer closeDstImg()
-  _, err = io.Copy(dstImg, srcImg)
-  return err
+func copyDiskImage(dst, src string) (err error) {
+	// Open source disk image
+	srcImg, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	closeSrcImg := func() {
+		if ee := srcImg.Close(); ee != nil {
+			err = ee
+		}
+	}
+	defer closeSrcImg()
+	dstImg, err := os.Create(dst)
+	if err != nil {
+		return err
+	}
+	closeDstImg := func() {
+		if ee := dstImg.Close(); ee != nil {
+			err = ee
+		}
+	}
+	defer closeDstImg()
+	_, err = io.Copy(dstImg, srcImg)
+	return err
 }
 
 // Make a boot2docker VM disk image with the given size (in MB).