Change default database path and configuration directory

Now respectively ${LOCALSTATEDIR}/lib/ndn/ndns/ndns.db
and ${SYSCONFDIR}/ndn/ndns

Refs: #4810
Change-Id: I351a6a15f8daa0a032845cb26d5d76179faa7b27
diff --git a/ndns.conf.sample.in b/ndns.conf.sample.in
index e595004..09521a3 100644
--- a/ndns.conf.sample.in
+++ b/ndns.conf.sample.in
@@ -1,7 +1,7 @@
 zones
 {
-  ; dbFile @DEFAULT_DATABASE_PATH@/ndns.db
-  ; validatorConfigFile @DEFAULT_CONFIG_PATH@/validator.conf
+  ; dbFile @DEFAULT_DBFILE@
+  ; validatorConfigFile @CONFDIR@/validator.conf
 
   zone
   {