Destroy ECMap instances on deactivate

Change-Id: I2437582b8d878bbf57d8447cb7d93636c9fc0246
(cherry picked from commit 0fa172fd1bf39495b1f763bbfead6257e815027a)
diff --git a/core/store/dist/src/main/java/org/onosproject/store/device/impl/GossipDeviceStore.java b/core/store/dist/src/main/java/org/onosproject/store/device/impl/GossipDeviceStore.java
index 842274a..3d106c9 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/device/impl/GossipDeviceStore.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/device/impl/GossipDeviceStore.java
@@ -252,7 +252,7 @@
 
     @Deactivate
     public void deactivate() {
-
+        devicePortStats.destroy();
         executor.shutdownNow();
 
         backgroundExecutor.shutdownNow();