Do not output usage hint when shell=none. Since there is no shell,

there is no clear way to expect how a usage hint will be interpretted.

Author: jtzwu

Diff for: pkg/minikube/shell/shell.go

@@ -124,10 +124,7 @@ REM @FOR /f "tokens=*" %%i IN ('%s') DO @%%i
 		unsetSuffix:    "\n",
 		unsetDelimiter: "",
 		usageHint: func(s ...interface{}) string {
-			return fmt.Sprintf(`
-# %s
-# eval $(%s)
-`, s...)
+			return  ""
 		},
 	},
 }