Remove alert for Internet Explorer 8 and below

Internet Explorer 8 was released in 2009 and people using it already
know that most web pages look broken on it, so we don't need to warn
them.

Removing it makes our application layout file much easier to read and
modify.

app/views/layouts/application.html.erb

@@ -17,34 +17,11 @@
 
     <div class="wrapper <%= yield(:wrapper_class) %>">
       <%= render "layouts/header", with_subnavigation: true %>
-
-      <% if request.headers["User-Agent"] =~ /MSIE/ && cookies["ie_alert_closed"] != "true" %>
-      <!--[if lt IE 9]>
-        <div data-alert class="callout primary ie-callout" data-closable>
-          <button class="close-button ie-callout-close-js"
-                  aria-label="<%= t("application.close") %>" type="button" data-close>
-            <span aria-hidden="true">&times;</span>
-          </button>
-          <h2><%= t("layouts.application.ie_title") %></h2>
-          <p>
-            <%= sanitize(t("layouts.application.ie",
-                           chrome: link_to(t("layouts.application.chrome"),
-                                           "https://www.google.com/chrome/browser/desktop/",
-                                           title: t("shared.target_blank"),
-                                           target: "_blank"),
-                           firefox: link_to(t("layouts.application.firefox"),
-                                            "https://www.mozilla.org/firefox",
-                                            title: t("shared.target_blank"),
-                                            target: "_blank"))) %>
-          </p>
-        </div>
-      <![endif]-->
-      <% end %>
-
       <%= render "layouts/flash" %>
 
       <%= yield %>
     </div>
+
     <div class="footer">
       <%= render Layout::FooterComponent.new %>
     </div>