views/modals/intro.html: generic-ify another URL

Ideally we should be using userweb_url_prefix here but I need to discover how to
parametrize that in an Angular template.

views/modals/intro.html

@@ -11,7 +11,7 @@
                localize-only="alt" />
         </a>
 
-        <a href="//worldwidetelescope.org/home" target="_blank"
+        <a href="/home" target="_blank"
            style="display:inline-block;position:relative;left:-3px;margin-right:7px;z-index:5" class="pull-left">
           <img ng-src='Images/wwtlogo.png'
                style="width:110px;height:110px;"