test-cat-file.sh: use -l instead of -b; explain differences.
test-cat-file.sh: use -l instead of -b; explain differences.

It turns out that cmp -b doesn't work on at least NetBSD, so use -l
instead, and when there's a problem, diff the "bup meta" output as
well.

Thanks to Thomas Klausner <tk@giga.or.at> for the report.

Signed-off-by: Rob Browning <1dc5917c2adeeba13d1ef33dbb40691a1b67cc65@defaultvalue.org>

mhoeher/bup,ToxicFrog/bup,jbaber/bup,jbaber/bup,gevaerts/bup,ToxicFrog/bup,ToxicFrog/bup,mhoeher/bup,pombredanne/bup,gevaerts/bup,pombredanne/bup,tjanez/bup,pombredanne/bup,gevaerts/bup,tjanez/bup,tjanez/bup,mhoeher/bup,mhoeher/bup,tjanez/bup,gevaerts/bup,mhoeher/bup,jbaber/bup,ToxicFrog/bup,jbaber/bup,jbaber/bup,tjanez/bup,pombredanne/bup,tjanez/bup,gevaerts/bup,mhoeher/bup,ToxicFrog/bup,pombredanne/bup,pombredanne/bup,jbaber/bup