moving random.go from utils

Closes #10962
Signed-off-by: Srini Brahmaroutu <srbrahma@us.ibm.com>

utils/random.go

@@ -1,16 +0,0 @@
-package utils
-
-import (
-	"crypto/rand"
-	"encoding/hex"
-	"io"
-)
-
-func RandomString() string {
-	id := make([]byte, 32)
-
-	if _, err := io.ReadFull(rand.Reader, id); err != nil {
-		panic(err) // This shouldn't happen
-	}
-	return hex.EncodeToString(id)
-}

utils/utils.go

@@ -21,6 +21,7 @@ import (
 	log "github.com/Sirupsen/logrus"
 	"github.com/docker/docker/autogen/dockerversion"
 	"github.com/docker/docker/pkg/archive"
+	"github.com/docker/docker/pkg/common"
 	"github.com/docker/docker/pkg/fileutils"
 	"github.com/docker/docker/pkg/ioutils"
 )
@@ -311,7 +312,7 @@ var globalTestID string
 // new directory.
 func TestDirectory(templateDir string) (dir string, err error) {
 	if globalTestID == "" {
-		globalTestID = RandomString()[:4]
+		globalTestID = common.RandomString()[:4]
 	}
 	prefix := fmt.Sprintf("docker-test%s-%s-", globalTestID, GetCallerName(2))
 	if prefix == "" {