Fix ansible-lint complaint about directory permissions

Switch from quoted string to actual octal number format

Change-Id: Ie188dc7cab2072a94395732c002443d10fcb1cae

tasks/nova_init_systemd.yml

@@ -19,7 +19,7 @@
     state: directory
     owner: "{{ system_user }}"
     group: "{{ system_group }}"
-    mode: "2755"
+    mode: 02755
   with_items:
     - { path: "/var/run" }
     - { path: "/var/lock" }