Use GnuPG 2 for backup/restore
    
    ipa-backup and ipa-restore now use GnuPG 2 for asymmetric encryption, too.
    The gpg2 command behaves a bit different and requires a gpg2 compatible
    config directory. Therefore the --keyring option has been deprecated.
    
    The backup and restore tools now use root's GPG keyring by default.
    Custom configuration and keyring can be used by setting GNUPGHOME
    environment variables.
    
    Fixes: https://pagure.io/freeipa/issue/7560
    Signed-off-by: Christian Heimes <cheimes@redhat.com>
    Reviewed-By: Rob Crittenden <rcritten@redhat.com>