Always show title of floating dockwidget.

Task-number:QTCREATORBUG-13325
Change-Id: I07ca3c6061855dcef31071ad3c143413d370b3aa
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>
Reviewed-by: Christian Stenger <christian.stenger@digia.com>