FIX: process when task author not attached

abonapp/locale/ru/LC_MESSAGES/django.po

@@ -1156,3 +1156,6 @@ msgstr "Открыть"
 
 msgid "Auto continue service."
 msgstr "Автопродление услуги."
+
+msgid "No author attached"
+msgstr "Автор не назначен"

abonapp/templates/abonapp/task_log.html

@@ -20,7 +20,13 @@
                 <td class="text-center"><a href="{% url 'taskapp:edit' task.pk %}" class="btn btn-default" title="{% trans 'View' %}" data-toggle="tooltip">
                     <span class="glyphicon glyphicon-eye-open"></span>
                 </a></td>
-                <td><a href="{% url 'acc_app:other_profile' task.author.id %}">{{ task.author.get_short_name }}</a></td>
+                <td>
+                    {% if task.author %}
+                        <a href="{% url 'acc_app:other_profile' task.author.id %}">{{ task.author.get_short_name }}</a>
+                    {% else %}
+                        {% trans 'No author attached' %}
+                    {% endif %}
+                </td>
                 <td>
                     {% for rec in task.recipients.all %}
                         <a href="{% url 'acc_app:other_profile' rec.id %}">{{ rec.get_short_name }}</a>