Improve log rotation for keystone

This change addresses 2 things:

1 ) After log rotation, keystone.log does not get appended
with new lines.
Flag copytruncate in logrotate address this by truncating the
log file instead of moving after compressing.

2 ) Doubles the size of the file to allow for more information
to be logged. With proper access logging now, which logs every
request, it's necessary have a bigger size.

Test plan:

PASS: Run a full build, install, bootstrap and unlock.
      Install DC system with subclouds. Fm alarm list.
PASS: Verify that /var/log/keystone/keystone.log has information
      in the format specified.

Story: 2011106
Task: 51139

Change-Id: I87696b66fb7cf3a4a015e302e2bde0583b0a6918
Signed-off-by: Rei Oliveira <Reinildes.JoseMateusOliveira@windriver.com>

syslog-ng-config/debian-source/syslog-ng.logrotate

@@ -24,7 +24,6 @@
 /var/log/sysinv-api.log
 /var/log/nfv-vim-api.log
 /var/log/nfv-vim-webserver.log
-/var/log/keystone/*.log
 /var/log/horizon.log
 /var/log/barbican/barbican-keystone-listener.log
 /var/log/barbican/barbican-worker.log
@@ -42,6 +41,22 @@
         endscript
 }
 
+/var/log/keystone/*.log
+{
+        nodateext
+        size 20M
+        start 1
+        rotate 20
+        copytruncate
+        missingok
+        notifempty
+        compress
+        sharedscripts
+        postrotate
+                 systemctl reload syslog-ng > /dev/null 2>&1 || true
+        endscript
+}
+
 /var/log/rss-memory.log
 /var/log/collectd.log
 {