updated bootstrap and bootswatch css on installer template, closes #6033

src/views/install/index.tpl

@@ -6,7 +6,7 @@
     <meta name="viewport" content="width=device-width, initial-scale=1">
 	<title>NodeBB Web Installer</title>
 
-	<link rel="stylesheet" type="text/css" href="https://bootswatch.com/united/bootstrap.min.css">
+	<link rel="stylesheet" type="text/css" href="https://maxcdn.bootstrapcdn.com/bootswatch/3.3.7/united/bootstrap.min.css">
 	<link href='https://fonts.googleapis.com/css?family=Roboto:400,300,500,700' rel='stylesheet' type='text/css'>
 	<link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/font-awesome/4.3.0/css/font-awesome.min.css">
 	<link rel="stylesheet" type="text/css" href="installer.css">
@@ -133,7 +133,7 @@
 	</div>
 
 	<script src="//code.jquery.com/jquery-1.11.2.min.js"></script>
-	<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.4/js/bootstrap.min.js"></script>
+	<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
 	<script type="text/javascript" src="installer.min.js"></script>
 </body>
 </html>