Add "http:" to the respec URL so that respec runs when viewing locally

spec/shadow/index.html

@@ -1,12 +1,12 @@
-<!DOCTYPE html>
+<!DOCTYPE html>
 <html>
   <head>
     <meta charset='utf-8'/>
     <title>Shadow DOM</title>
     <script src='./autolink-config.js' class='remove'></script>
     <script src='../../assets/scripts/autolink.js' class='remove'></script>
     <link rel="stylesheet" href="../../assets/styles/respec-complement.css" type="text/css" />
-    <script src='//www.w3.org/Tools/respec/respec-w3c-common' async class='remove'></script>
+    <script src='http://www.w3.org/Tools/respec/respec-w3c-common' async class='remove'></script>
     <script class='remove'>
       var respecConfig = {
           specStatus: "ED",