spec: janitorial: drop with_systemd_macros and with_tmpfiles

Nowadays we can assume that /usr/lib/tmpfiles.d and systemd_macros exist
whenever systemd does.

Change-Id: I9b27480cf2a40575f500e68ae4aebf36d7363e90
Signed-off-by: Dan Kenigsberg <danken@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/33380
Reviewed-by: Douglas Schilling Landgraf <dougsland@redhat.com>
Reviewed-by: Yaniv Bronhaim <ybronhei@redhat.com>