Warn our users about Nova API in WSGI with Apache

It was suggested by Nova team to not deploying Nova API in WSGI with
Apache in production.
It's causing some issues that we didn't catch until now (see in the bug
report).

Change-Id: I163c85337437704ec3668fc9fa5e2c40eb23248c
Related-Bug: 1661360

manifests/wsgi/apache_api.pp

@@ -110,6 +110,8 @@ class nova::wsgi::apache_api (
     fail('::nova::api class must be declared in composition layer.')
   }
 
+  warning('deploying Nova API in WSGI with Apache is not recommended by Nova team. See LP#1661360.')
+
   ::openstacklib::wsgi::apache { 'nova_api_wsgi':
     bind_host                 => $bind_host,
     bind_port                 => $api_port,

releasenotes/notes/nova_wsgi-a9ee8c336a67a7ac.yaml

@@ -0,0 +1,5 @@
+---
+issues:
+  - Using nova::wsgi::apache_api to deploy Nova in WSGI with Apache is not
+    recommended by Nova team. See `bug 1661360
+    <https://bugs.launchpad.net/nova/+bug/1661360>`__.