Copied from dpkg-1.16.10/debian/dpkg.postinst, on post install, runs create_database, create_logfile.
    
    - Based on dpkg.install and dselect.install
      created some missing directories in /var/lib/dpkg and in /etc/dpkg .
    - Drop Requirement dpkg of dpkg-perl.
    - Fix a FIXME , all perls moved to dpkg-perl.
    - TODO: set logrotates, see debian/dpkg.logrotate.