Bug 33168: Prevent debhelper from renaming history.txt to changelog

Bug 33168: Prevent debhelper from renaming history.txt to changelog

This change prevents debhelper from renaming history.txt to changelog,
since that renaming was breaking the Timeline feature in Koha.

Another option would've been to rename history.txt to something else
but that filename is already embedded in Koha and the Koha release
tools, so this seems the safer option.

Test plan:
0. Apply patch
1. Build Debian package
2. Confirm that /usr/share/doc/koha-common/history.txt is created
and /usr/share/doc/koha-common/changelog.gz is not created

Signed-off-by: Mason James <mtj@kohaaloha.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>