Remove unused attribute

Signed-off-by: Michal Čihař <michal@cihar.com>

weblate/html/last-changes.html

@@ -4,7 +4,7 @@
 
 <div class="panel panel-primary">
 <div class="panel-heading">
-<h4 class="panel-title">{% if history_title %}{{ history_title }}{% else %}{% trans "History" %}{% endif %}</h4>
+<h4 class="panel-title">{% trans "History" %}</h4>
 </div>
 <div class="panel-body">