build-debian.sh: Rename tmp.deb to tmp.debian so "*.deb" works correctly

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
build-debian.sh: tee the lintian output, for the impatient

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
release.sh: Sign output conditionally

Add the same check that's in build-debian.sh

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Fix up return value checks on read() / fread()

fread() might return 0 on error, or it might set ferror().  It will never
return a negative number.

read() returns a ssize_t.

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
travis: Initial commit