Add checking if user has access to admin (user.is_staff) before

showing "Go to admin" button in error template.

suit/templates/suit/error_base.html

@@ -89,7 +89,7 @@ <h1>{% block title %}Error{% endblock %}</h1>
           if (document.referrer != '') {
               document.write('<a href="javascript:history.back()" class="btn btn-info btn-large">Go back</a> ');
           }
-          {% if request and user.is_authenticated %}
+          {% if request and user.is_authenticated and user.is_staff %}
           document.write('<a href="{% url 'admin:index' %}" class="btn btn-large">Go to admin home</a> ');
           {% endif %}
       }