ACK/Cmnt: [Plucky/Unstable PATCH] UBUNTU: [Packaging] replace $(DROOT) with debian

[Agathe Porte]

2024-10-30 12:19 CET, Masahiro Yamada:
> If DROOT is not set to 'debian', our debian scripts do not work at all.
> This variable is therefore not useful.

Agreed. I checked in a derivative and it does not seem to be changed
unlike the DEBIAN variable. Also it is shorter to type, which is nice:

	$ echo '$(DROOT)/' | wc -c
	10

	$ echo 'debian/' | wc -c
	8

Finally we already use debian/ in some of these files so this will allow
us to be consistent.

Acked-by: Agathe Porte <agathe.porte at canonical.com>