Fix space before commas for administrator judge list; DMOJ#78

(cherry picked from commit 3953111)

templates/problem/problem.html

@@ -216,7 +216,7 @@ <h2 id="h2Title" style="color:#393630; display: inline-block">{{ title }}</h2>
                     {% if perms.judge.change_judge %}
                         {% for judge in available_judges %}
                             <a href="{{ url('admin:judge_judge_change', judge.id) }}">{{ judge.name }}</a>
-                            {% if not loop.last %}, {% endif %}
+                            {%- if not loop.last %}, {% endif %}
                         {% endfor %}
                     {% else %}
                         {{ available_judges|join(", ") }}