Ovsdb equals review fix

Change-Id: I5833f1446a882c7ff106a0bcfa15f4629cbdcae9
diff --git a/drivers/src/main/java/org/onosproject/driver/ovsdb/OvsdbControllerConfig.java b/drivers/src/main/java/org/onosproject/driver/ovsdb/OvsdbControllerConfig.java
index a00d3db..f116ab8 100644
--- a/drivers/src/main/java/org/onosproject/driver/ovsdb/OvsdbControllerConfig.java
+++ b/drivers/src/main/java/org/onosproject/driver/ovsdb/OvsdbControllerConfig.java
@@ -16,6 +16,7 @@
 
 package org.onosproject.driver.ovsdb;
 
+import com.google.common.collect.ImmutableSet;
 import org.onlab.packet.IpAddress;
 import org.onlab.packet.TpPort;
 import org.onosproject.net.AnnotationKeys;
@@ -56,7 +57,7 @@
         DriverHandler handler = handler();
         OvsdbClientService clientService = getOvsdbClientService(handler);
         if (!clientService.getControllers(handler().data().deviceId())
-                .equals(controllers)) {
+                .equals(ImmutableSet.copyOf(controllers))) {
             clientService.setControllersWithDeviceId(handler().
                     data().deviceId(), controllers);
         }