Fix scope of vhost template variables

Dynamic scoping for variables in ERB templates was removed in puppet
4[1] which means that the variables defined in the manifests cannot be
found when it is referenced in the httpd::vhost defined type and will be
evaluated as nil when puppet runs. Use scope.lookupvar instead to be
explicit about the variable's source.

[1] https://puppet.com/docs/puppet/4.10/lang_updating_manifests.html#dynamic-scoping-in-erb

Change-Id: I007975c920bd12a352acdea742b841a17ecc5d17

templates/storyboard_http.vhost.erb

@@ -15,7 +15,7 @@
   CustomLog ${APACHE_LOG_DIR}/storyboard-access.log combined
 
   <Directory "<%= scope.lookupvar("storyboard::application::install_root") %>">
-    <% if @new_vhost_perms %>
+    <% if scope.lookupvar("storyboard::application::new_vhost_perms") %>
       Require all granted
     <% else %>
       Order allow,deny

templates/storyboard_https.vhost.erb

@@ -55,7 +55,7 @@
     WSGIPassAuthorization On
 
     <Directory "<%= scope.lookupvar("storyboard::application::install_root") %>">
-      <% if @new_vhost_perms %>
+      <% if scope.lookupvar("storyboard::application::new_vhost_perms") %>
         Require all granted
       <% else %>
         Order allow,deny