Univention Corporate Server 4.0 erratum 197 (bugfix)

This update addresses the following issues:
* It is now possible to create a core dump of the UMC-Webserver.
* A check for free disk space is now only done once per file upload request.
* The place holders in the login dialogue are now diplayed correctly in
  Internet Explorer 9.
* Scrolling in the appcenter on mobile devices is now more responsive.