Update non-firefox copy to be less rude. (bug 666445)

templates/impala/base.html

@@ -100,12 +100,11 @@
             {% endblock %}
           </div>
           <div class="site-balloon" id="site-nonfx">
-            <h3>{{ _('Aren’t you forgetting something?') }}</h3>
             <p>
               {% trans url='http://mozilla.org/firefox/?src=amo' %}
-                To use the thousands of add-ons available here, download
-                <a href="{{ url }}">Mozilla Firefox</a>
-                &mdash; a fast, free Web browser.
+                To try the thousands of add-ons available here, download
+                <a href="{{ url }}">Mozilla Firefox</a>,
+                a fast, free way to surf the Web!
               {% endtrans %}
             </p>
             <a href="#" class="close">{{ _('Close') }}</a>