Ignore error in activity timeline caused by invalid data.

src/main/twirl/helper/activities.scala.html

@@ -12,6 +12,7 @@
         @activityMessage(activity.message)
       </div>
       @activity.additionalInfo.map { additionalInfo =>
+        @if(additionalInfo.nonEmpty){
           @(activity.activityType match {
             case "create_wiki" => {
               <div class="small activity-message">Created <a href={s"${path}/${activity.userName}/${activity.repositoryName}/wiki/${additionalInfo}"}>{additionalInfo}</a>.</div>
@@ -38,6 +39,7 @@
             }
           })
         }
+      }
     </div>
   }
 }