Hiding the View Differences button when a wiki page's history only has one version.

Patch contributed by Chaoqun Zou (#1743)


git-svn-id: http://redmine.rubyforge.org/svn/trunk@1749 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/views/wiki/history.rhtml

@@ -30,6 +30,6 @@
 <% end %>
 </tbody>
 </table>
-<%= submit_tag l(:label_view_diff), :class => 'small' %>
+<%= submit_tag l(:label_view_diff), :class => 'small' if show_diff %>
 <span class="pagination"><%= pagination_links_full @version_pages, @version_count, :page_param => :p %></span>
 <% end %>