Keep logs for 10 rotations by default

By default openstack services do rotation on dayly basis, at the
same time we keep only 4 rotations by default, as result logs are
keept for 4 days. This patch increases this value to 10 by default.

Change-Id: I7338f7b4e1fceebda6a70b52dd592f866ccd0bed
Related-Prod: PROD-24376
diff --git a/linux/system/single/simple.yml b/linux/system/single/simple.yml
index 45be219..39ad157 100644
--- a/linux/system/single/simple.yml
+++ b/linux/system/single/simple.yml
@@ -6,6 +6,7 @@
 parameters:
   _param:
     local_package_repos: false
+    logrotate_keep_rotate: 10
   linux:
     system:
       at:
@@ -24,3 +25,7 @@
         en_US.UTF-8:
           enabled: true
           default: true
+  logrotate:
+    server:
+      global_conf:
+        keep_rotate: ${_param:logrotate_keep_rotate}