Univention Corporate Server 4.1 erratum 249 (bugfix)

This update addresses the following issue(s):
* The UCR variable ldap/limits has been added to configure OpenLDAP server
  limits.
* The slapd backup cronjob can now be disabled by setting the UCR
  variable slapd/backup to false. The cron interval can be configured with
  the UCR variable slapd/backup/cron. 
* The ldap client paramaters NETWORK_TIMEOUT, TIMEOUT and TIMELIMIT can
  now be configured with the UCR variables ldap/client/network_timeout,
  ldap/client/timeout and ldap/client/timelimit.
* The index lines in the slapd.conf are now wrapped if the line is longer
  than 2048 characters.
* The UCR variable ldap/index/quickmode has been added. If set to true
  the LDAP reindex tool (ldap_setup_index) is started in quick mode
  (fewer integrity checks, improved indexing time)