systemd: fix grains

systemd/init.sls

 systemd_pkgs:
   pkg.latest:
 {%- if grains['osmajorrelease'] >= 9 and grains['osmajorrelease'] <= 12 %}
-    - fromrepo: {{ oscodename }}-backports
+    - fromrepo: {{ grains['oscodename'] }}-backports
 {%- endif %}
     - pkgs:
       - systemd