Add log_format variable for apache openstack sites

Add openstack default variables with log formats for apache sites

Aligh log settings with settings from formulas for openstack
services: aodh, barbican, cinder, gnocchi, manila, nova-placement,
panko.

Change-Id: Ie59d341c39e9c50292f4fe28c6227766961d250c
PROD-Related: PROD-28066 (PROD:28066)
(cherry picked from commit 3369142157ac5b705955b9b8754124c4c24cbd4f)
diff --git a/apache/server/site/nova-placement.yml b/apache/server/site/nova-placement.yml
index 7c8e8bd..a869fea 100644
--- a/apache/server/site/nova-placement.yml
+++ b/apache/server/site/nova-placement.yml
@@ -37,8 +37,7 @@
             port: 8778
           log:
             custom:
-              format: >-
-                %v:%p %{X-Forwarded-For}i %h %l %u %t \"%r\" %>s %D %O \"%{Referer}i\" \"%{User-Agent}i\"
+              format: ${_param:apache_site_openstack_placement_log_format}
               file: '/var/log/apache2/nova_placement_access.log'
             error:
               enabled: true