Define template version in certmap.conf
    
    A previous commit (ffb9a09a0d63f7edae2b647b5c1d503d1d4d7a6e) removed the
    definition of VERSION 2 in certmap.conf.template.
    
    ipa-server-upgrade tool compares the template version with the version in
    certmap.conf. As VERSION is not defined in either file, it concludes that
    version = 0 for both and does not make a backup of certmap.conf even though
    it prints that it will.
    
    The fix re-defines VERSION in the template and adapts the code because the
    template has changed (it is using $ISSUER_DN instead of
    CN=Certificate Authority,$SUBJECT_BASE).
    
    The fix also logs an error when a template file is not versioned.
    
    https://fedorahosted.org/freeipa/ticket/6354
    
    Reviewed-By: Tomas Krizek <tkrizek@redhat.com>