Add posibility to configure logfile param

Change-Id: Iac37132f89dab9b489b864070022c5ddc926d006
diff --git a/tests/pillar/server.sls b/tests/pillar/server.sls
index 5287e83..b623e0c 100644
--- a/tests/pillar/server.sls
+++ b/tests/pillar/server.sls
@@ -1,6 +1,7 @@
 ntp:
   server:
     enabled: true
+    logfile: '/var/log/ntp.log'
     mode7: true
     orphan: 5
     peers:
@@ -15,4 +16,4 @@
       subnet: 172.16.1.1
     strata:
     - ntp.cesnet.cz
-    - pool.ntp.org
\ No newline at end of file
+    - pool.ntp.org