Add unit tests for OpenstackNetworkingUtil.

Change-Id: I86f573564bcc16df69e0b69ff623c68101b399d1
diff --git a/apps/openstacknode/app/src/main/java/org/onosproject/openstacknode/util/OpenstackNodeUtil.java b/apps/openstacknode/app/src/main/java/org/onosproject/openstacknode/util/OpenstackNodeUtil.java
index 095d2bc..fac184e 100644
--- a/apps/openstacknode/app/src/main/java/org/onosproject/openstacknode/util/OpenstackNodeUtil.java
+++ b/apps/openstacknode/app/src/main/java/org/onosproject/openstacknode/util/OpenstackNodeUtil.java
@@ -49,7 +49,7 @@
  * An utility that used in openstack node app.
  */
 public final class OpenstackNodeUtil {
-    protected static final Logger log = LoggerFactory.getLogger(OpenstackNodeUtil.class);
+    private static final Logger log = LoggerFactory.getLogger(OpenstackNodeUtil.class);
 
     // keystone endpoint related variables
     private static final String DOMAIN_DEFAULT = "default";