rpm: Pick debugfs package db files/dirs explicitly

Rather than copying the entire /etc hierarchy, specify the pieces we
actually need.

Signed-off-by: Alex Kiernan <alex.kiernan@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
(cherry picked from commit f0fea55a)
Signed-off-by: Steve Sakoman <steve@sakoman.com>