Univention Corporate Server 4.1 erratum 123 (bugfix)

This update addresses the following issue(s):
* The application information like vendor, description were HTML encoded
  twice at some places.
* If no package changes are detected an application could not be upgraded.
* The error handling of the apps module has been improved.
* The application metadata are ensured to be updated before installing or
  upgrading an application. This prevents errors when installing applications
  on remote hosts.