nginx config should be provided in the postrotate command

otherwise signal is sent to the nginx with the default configuration
file which causes error.log being created in the wrong location.
Also if SELinux is turned on the box, logrotate breaks due to the fact
that the logrotate_exec_t service can not modify files labeled usr_t.
Default error.log locates in the
/opt/opscode/embedded/nginx/logs/error.log and labeled as usr_t.

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Chef Server Changelog
 
+## (unknown)
+
+### private-chef-cookbooks/private-chef
+- Fix logrotate configuration to make it work with SELinux enabled.
+
 ## [12.8.0](https://github.com/chef/chef-server/tree/12.8.0) (2016-07-06)
 [Full Changelog](https://github.com/chef/chef-server/compare/12.7.0...12.8.0)
 

omnibus/files/private-chef-cookbooks/private-chef/recipes/nginx.rb

@@ -177,7 +177,7 @@
   group 'root'
   mode '0644'
   variables(node['private_chef']['nginx'].to_hash.merge(
-    'postrotate' => '/opt/opscode/embedded/sbin/nginx -s reopen',
+    'postrotate' => "/opt/opscode/embedded/sbin/nginx -c #{nginx_config} -s reopen",
     'owner' => OmnibusHelper.new(node).ownership['owner'],
     'group' => OmnibusHelper.new(node).ownership['group']
   ))