packaging: spec: fix distro macros

Fix distro macros causing CentOS build failures.

Change-Id: I61283cbf6fc5697f0dd80f92648b69287921bb30
Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>
(cherry picked from commit 8380f846f29446075a7bff5a96ddddb32e4223ca)