According to the apt_preferences man page, we should be able to use
"Package: src:zfsutils-linux". Then we don't have to worry about keeping
the list of packages up-to-date, especially as library soversions change.
Reported-by: udf2457
Closes#314
Signed-off-by: Richard Laager <rlaager@wiktel.com>
36c1f2f5cd