Univention Corporate Server 4.4 erratum 25 (bugfix)

This update addresses the following issues:
* The SAML identity provider is not configured in the UMC-WebServer anymore
  if it is disabled via the UCR variable umc/web/sso/enabled.
* The UCS identity provider configuration is always fetched when executing
  the joinscript 92univention-management-console-web-server.inst
* The UMC now uses json instead of simplejson.
* The error message for a failed password change has been improved.
* Obsolete code has been removed.