Univention Corporate Server 4.3 erratum 2 (bugfix)

This update addresses the following issue(s):
* The development tools did not prepend http:// to the call for "zsyncmake".
  This caused problems and has been fixed.
* While updating from UCS 4.2 to UCS 4.3, some Apps changed their version.
  This requires a re-registration of the Apps.
* Calling univention-upgrade noninteractively may have caused an error while
  upgrading Apps when run on a DC Master.