Merge pull request #957 from edx/jarv/fix-var

switch to old style var

playbooks/roles/edxapp/defaults/main.yml

@@ -442,7 +442,7 @@ lms_auth_config:
 
 lms_env_config:
   <<: *edxapp_generic_env
-  PAID_COURSE_REGISTRATION_CURRENCY: "{{ EDXAPP_PAID_COURSE_REGISTRATION_CURRENCY }}"
+  PAID_COURSE_REGISTRATION_CURRENCY: $EDXAPP_PAID_COURSE_REGISTRATION_CURRENCY
   'CODE_JAIL':
     # from https://github.com/edx/codejail/blob/master/codejail/django_integration.py#L24, '' should be same as None
     'python_bin': '{% if EDXAPP_PYTHON_SANDBOX %}{{ edxapp_sandbox_venv_dir }}/bin/python{% endif %}'