Remove /meta_searches/tags page.

This was a search page that let you search for tags, aliases, and
implications at the same time. It never got much use and it's been
broken for a while now (the search form passed the wrong param to the
controller).

app/views/static/site_map.html.erb

@@ -54,7 +54,6 @@
         <li><%= link_to("Aliases", tag_aliases_path) %></li>
         <li><%= link_to("Implications", tag_implications_path) %></li>
         <li><%= link_to("Listing", tags_path) %></li>
-        <li><%= link_to("Search", meta_searches_tags_path) %></li>
       </ul>
       <ul>
         <li><h1>Notes</h1></li>