Enable logging.conf & fluentd for glance

This change introduce ability to use log_config_append parameter with
new FluentdHandler to send logs directly to Fluentd.

To save per binary log streams as it is in the default logging states generates
separate logging.conf files per service and use /etc/default/<service name>
to pass dedicated logging.conf to every service.

Change-Id: Ie592faf9c91c71d5cc551bac62b25a19f04eb691
Related-Prod: PROD-16324
diff --git a/README.rst b/README.rst
index 415c31f..f693d68 100644
--- a/README.rst
+++ b/README.rst
@@ -322,6 +322,30 @@
               protected: false
               location: http://download.cirros-cloud.net/0.3.4/cirros-0.3.4-i386-disk.img
 
+Enhanced logging with logging.conf
+----------------------------------
+
+By default logging.conf is disabled.
+
+That is possible to enable per-binary logging.conf with new variables:
+  * openstack_log_appender - set it to true to enable log_config_append for all OpenStack services;
+  * openstack_fluentd_handler_enabled - set to true to enable FluentHandler for all Openstack services.
+
+Only WatchedFileHandler and FluentHandler are available.
+
+Also it is possible to configure this with pillar:
+
+.. code-block:: yaml
+
+  glance:
+    server:
+      logging:
+        log_appender: true
+        log_handlers:
+          watchedfile:
+            enabled: true
+          fluentd:
+            enabled: true
 
 Usage
 =====