Univention Corporate Server 4.4 erratum 497 (bugfix)

This update addresses the following issues:
* The init script for `slapd` now looks for running process only below parent
  PID 1 specifically. This allows running other `slapd` processes in
  containers.
* The 'slapo-lastbind' LDAP overlay can now be activated via the UCR variable
  `ldap/overlay/lastbind` which when activated stores the time-stamp of a
  successful bind to an LDAP server. The script
  `/usr/share/univention-ldap/univention_lastbind.py` can be used to store
  the youngest of these timestamps, from all reachable LDAP servers, into the
  `lastbind` extended attribute of a specified user.