put the apros upstream def back

The lms role gets installed first.  by referencing this upstream server,
we introduce a dependency on the upstream definition before it is
defined by the apros role.

playbooks/roles/nginx/templates/edx/app/nginx/sites-available/lms.j2

@@ -11,6 +11,12 @@ upstream lms-backend {
 
 }
  
+upstream apros_app_server {
+    {% for host in nginx_apros_gunicorn_hosts %}
+      server {{host}}:{{mcka_apros_gunicorn_port}} fail_timeout=0;
+    {% endfor %}
+}
+
 {%- if EDXAPP_ENABLE_RATE_LIMITING -%}
 # Make Zone
 limit_req_zone $cookie_{{ EDXAPP_SESSION_COOKIE_NAME }} zone=cookies:10m rate={{ EDXAPP_COURSES_REQUEST_RATE }};