Amend wiki listing and general timezone formats (fixes #2649)

app/helpers/application_helper.rb

@@ -76,8 +76,7 @@ module ApplicationHelper
   end
 
   def time_tag(content, time)
-    zone = time.strftime("%z")
-    datetime = time.strftime("%Y-%m-%dT%H:%M" + zone[0, 3] + ":" + zone[3, 2])
+    datetime = time.strftime("%Y-%m-%dT%H:%M%:z")
 
     content_tag(:time, content || datetime, :datetime => datetime, :title => time.to_formatted_s)
   end

app/views/wiki_pages/index.html.erb

@@ -16,7 +16,7 @@
           <% @wiki_pages.each do |wiki_page| %>
             <tr>
               <td class="category-<%= wiki_page.category_name %>"><%= link_to wiki_page.pretty_title, wiki_page_path(wiki_page, :noredirect => 1) %></td>
-              <td><%= wiki_page.updated_at.strftime("%Y-%m-%d %I:%M") %> by <%= h link_to_user wiki_page.updater %></td>
+              <td><%= wiki_page.updated_at.strftime("%Y-%m-%d %H:%M") %> by <%= h link_to_user wiki_page.updater %></td>
             </tr>
           <% end %>
         </tbody>