Fix cat /etc/salt/grains.d/* when files not present

salt/minion/grains.sls

@@ -23,8 +23,8 @@ salt_minion_grains_file:
   cmd.run:
   - name: cat /etc/salt/grains.d/* > /etc/salt/grains
   - require:
-    - file: salt_minion_grains_dir
+    - file: salt_minion_grains_placeholder
   - watch_in:
     - service: salt_minion_service
 
-{%- endif %}
+{%- endif %}