Use global random *rand.Rand instance in pkg

Signed-off-by: Alexander Morozov <lk4d4@docker.com>
Upstream-commit: 51cdcf3c9df04a34945c976cfe2bdbad6fee122a
Component: engine

components/engine/pkg/stringutils/stringutils.go

@@ -14,9 +14,8 @@ func GenerateRandomAlphaOnlyString(n int) string {
 	// make a really long string
 	letters := []byte("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
 	b := make([]byte, n)
-	r := rand.New(random.NewSource())
 	for i := range b {
-		b[i] = letters[r.Intn(len(letters))]
+		b[i] = letters[random.Rand.Intn(len(letters))]
 	}
 	return string(b)
 }