Quote mode strings

Ansible turned 0640 into 420 and 0750 into 488, only one of which are
valid file modes.  Quotes prevent it from doing so too early.
Fixes d2f1595c.

playbooks/roles/edxapp/tasks/deploy.yml

@@ -17,9 +17,9 @@
     group: "{{ item.group }}"
     mode: "{{ item.mode }}"
   with_items:
-    - { src: 'edxapp_env.j2', dest: '{{ edxapp_app_dir }}/edxapp_env', owner: '{{ edxapp_user }}', group: '{{ common_web_user }}', mode: 0644 }
-    - { src: 'newrelic.ini.j2', dest: '{{ edxapp_app_dir }}/newrelic.ini', owner: '{{ edxapp_user }}', group: '{{ common_web_user }}', mode: 0644 }
-    - { src: 'git_ssh.sh.j2', dest: '{{ edxapp_git_ssh }}', owner: '{{ edxapp_user }}', group: '{{ edxapp_user }}', mode: 0750 }
+    - { src: 'edxapp_env.j2', dest: '{{ edxapp_app_dir }}/edxapp_env', owner: '{{ edxapp_user }}', group: '{{ common_web_user }}', mode: '0644' }
+    - { src: 'newrelic.ini.j2', dest: '{{ edxapp_app_dir }}/newrelic.ini', owner: '{{ edxapp_user }}', group: '{{ common_web_user }}', mode: '0644' }
+    - { src: 'git_ssh.sh.j2', dest: '{{ edxapp_git_ssh }}', owner: '{{ edxapp_user }}', group: '{{ edxapp_user }}', mode: '0750' }
   tags:
     - install
     - install:base