Adding some tests for GossipDeviceStore + bugfix

Change-Id: Ic0d55fa499b1d66131f059b4a47cd105c55a6e63
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/DeviceDescriptions.java b/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/DeviceDescriptions.java
index f7fd7bc..03c293a 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/DeviceDescriptions.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/DeviceDescriptions.java
@@ -58,7 +58,7 @@
      *
      * @param newDesc new DeviceDescription
      */
-    public synchronized void putDeviceDesc(Timestamped<DeviceDescription> newDesc) {
+    public void putDeviceDesc(Timestamped<DeviceDescription> newDesc) {
         Timestamped<DeviceDescription> oldOne = deviceDesc;
         Timestamped<DeviceDescription> newOne = newDesc;
         if (oldOne != null) {
@@ -76,7 +76,7 @@
      *
      * @param newDesc new PortDescription
      */
-    public synchronized void putPortDesc(Timestamped<PortDescription> newDesc) {
+    public void putPortDesc(Timestamped<PortDescription> newDesc) {
         Timestamped<PortDescription> oldOne = portDescs.get(newDesc.value().portNumber());
         Timestamped<PortDescription> newOne = newDesc;
         if (oldOne != null) {