avoids this warnig:

*** WARNING: ucf was run from a maintainer script that uses debconf, but
             the script did not pass --debconf-ok to ucf. The maintainer
             script should be fixed to not stop debconf before calling ucf,
             and pass it this parameter. For now, ucf will revert to using
             old-style, non-debconf prompting. Ugh!

             Please inform the package maintainer about this problem.

this avoids endless loops during configuration

this avoids endless loops during configuration

this prevented dpkg-reconfigure from working with debconf level set to
high or critical

* No longer hardcode path to tune2fs in config script
* Fix pending l10n issues. Debconf translations:
  - Spanish (Omar Campagne).  Closes: #537589
  - Japanese (Hideki Yamane (Debian-JP)).  Closes: #558074
  - Danish (Joe Hansen).  Closes: #582174

docbook-xsl is necessary to build the package without network access.