`${pkgbase}` was added to the wrong invocation. This ensures we are
producing correct debug packages.
Example from the package:
/usr/src/debug/pacman/pacman-6.0.2/src/pacman/callback.c
/usr/src/debug/pacman/pacman-6.0.2/src/pacman/callback.h
/usr/src/debug/pacman/pacman-6.0.2/src/pacman/check.c
/usr/src/debug/pacman/pacman-6.0.2/src/pacman/check.h
Fixes: 776b7c1e75 ("debugflags: Ensure we have unique source paths")
Signed-off-by: Morten Linderud <morten@linderud.pw>
Signed-off-by: Allan McRae <allan@archlinux.org>