Strage Internal Server Error, if openattic-gui is not installed.

        mod_wsgi (pid=28595): Exception occurred processing WSGI script '/usr/share/openattic/openattic.wsgi'.                          
        Traceback (most recent call last):
          File "/usr/lib/python2.7/dist-packages/django/core/handlers/wsgi.py", line 189, in __call__
            response = self.get_response(request)
          File "/usr/lib/python2.7/dist-packages/django/core/handlers/base.py", line 207, in get_response
            return debug.technical_500_response(request, *sys.exc_info(), status_code=400)
          File "/usr/lib/python2.7/dist-packages/django/views/debug.py", line 97, in technical_500_response
            html = reporter.get_traceback_html()
          File "/usr/lib/python2.7/dist-packages/django/views/debug.py", line 384, in get_traceback_html
            return t.render(c)
          File "/usr/lib/python2.7/dist-packages/django/template/base.py", line 210, in render
            return self._render(context)
          File "/usr/lib/python2.7/dist-packages/django/template/base.py", line 202, in _render
            return self.nodelist.render(context)
          File "/usr/lib/python2.7/dist-packages/django/template/base.py", line 905, in render
            bit = self.render_node(node, context)
          File "/usr/lib/python2.7/dist-packages/django/template/debug.py", line 79, in render_node
            return node.render(context)
          File "/usr/lib/python2.7/dist-packages/django/template/defaulttags.py", line 329, in render
            return nodelist.render(context)
          File "/usr/lib/python2.7/dist-packages/django/template/base.py", line 905, in render
            bit = self.render_node(node, context)
          File "/usr/lib/python2.7/dist-packages/django/template/debug.py", line 79, in render_node
            return node.render(context)
          File "/usr/lib/python2.7/dist-packages/django/template/debug.py", line 89, in render
            output = self.filter_expression.resolve(context)
          File "/usr/lib/python2.7/dist-packages/django/template/base.py", line 648, in resolve
            obj = self.var.resolve(context)
          File "/usr/lib/python2.7/dist-packages/django/template/base.py", line 789, in resolve
            value = self._resolve_lookup(context)
          File "/usr/lib/python2.7/dist-packages/django/template/base.py", line 849, in _resolve_lookup
            current = current()
          File "/usr/lib/python2.7/dist-packages/django/http/request.py", line 152, in build_absolute_uri
            host=self.get_host(),
          File "/usr/lib/python2.7/dist-packages/django/http/request.py", line 102, in get_host
            raise DisallowedHost(msg)