conf: Add log4cxx path to conf file

refs: #1950

Change-Id: I51f9217c6ee40fd49a53d5f8294b60fb306e82ee
diff --git a/nlsr.conf b/nlsr.conf
index 52ce870..31d9633 100644
--- a/nlsr.conf
+++ b/nlsr.conf
@@ -29,8 +29,9 @@
 
   log-level  INFO
 
-  log-dir /var/log/nlsr/  ; path for log directory (Absolute path)
-  seq-dir /var/lib/nlsr/  ; path for sequence directory (Absolute path)
+  log-dir       /var/log/nlsr/         ; path for log directory (Absolute path)
+  seq-dir       /var/lib/nlsr/         ; path for sequence directory (Absolute path)
+  ;log4cxx-conf /path/to/log4cxx-conf  ; path for log4cxx configuration file (Absolute path)
 }
 
 ; the neighbors section contains the configuration for router's neighbors and hello's behavior