Skip error entries in OPDS feed

src/views/opds/title.xml.ecr

@@ -21,6 +21,7 @@
   <% end %>
 
   <% title.entries.each do |e| %>
+    <% next if e.err_msg %>
       <entry>
         <title><%= HTML.escape(e.display_name) %></title>
         <id>urn:mango:<%= e.id %></id>
@@ -34,5 +35,4 @@
         <link type="text/html" rel="alternate" title="Open in Mango" href="<%= base_url %>book/<%= e.book.id %>" />
       </entry>
     <% end %>
-
   </feed>