remove rsyslog pinning from leap repository

Rsyslog has been in backports for a while now, but our apt preferences still use LEAPs repository. This should be cleaned up, I think, and point to backports:

class site_config::syslog {

  # we need to pull in rsyslog from the leap repository until it is availbale in
  # wheezy-backports
  apt::preferences_snippet { 'fixed_rsyslog_anon_package':
    package  => 'rsyslog*',
    priority => '999',
    pin      => 'release o=leap.se',
    before   => Class['rsyslog::install']
  }

(from redmine: created on 2014-04-20, closed on 2014-05-18)