Univention Corporate Server 4.2 erratum 40 (bugfix)

This update addresses the following issues:
* The reason why changing the password failed is shown again.
* An error during login via SAML has been fixed.
* A redirection loop during SAML login is prevented.
* The PAM configuration has been adjusted to make password changes
  possible again if the password was expired.
* The error handling on module initialization has been improved.
* If the URL to access UMC contained a Port a XSRF-Attack was wrong
  detected causing UMC to be unusable. This has been fixed.
* The link to send feedback to Univention has been fixed.
* A crash of the UMC-Server during handling of errors has been fixed.
* A notification about the Administrator account is shown when trying
  to login as root.
* After a failed attempt to change an expired user password via the
  login dialog the form fields weren't reset resulting in further
  authentication attempts being impossible.