Merge topic 'cpack-deb-minor-fixes'

ed1f3a5fa5 CPackDeb: output the error message when no description can be made
ece24b343a Help/cpack_gen/freebsd: improve wording for Debian fallbacks

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: Kyle Edwards <kyle.edwards@kitware.com>
Merge-request: !6196