Get rid of error when setting custom grains for the first time

salt/minion.sls

@@ -12,11 +12,19 @@ salt_minion_grains_dir:
   - makedirs: true
   - user: root
 
+salt_minion_grains_placeholder:
+  file.touch:
+  - name: /etc/salt/grains.d/placeholder
+  - user: root
+  - group: root
+  - require:
+    - file: salt_minion_grains_dir
+
 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
 
 /etc/salt/minion.d/minion.conf:
   file.managed: