Deprecate MastershipService::getDevicesOf method

Change-Id: I79ac1cbd7765229d39a5e2c614c98f17760f52a1

@@ -124,7 +124,9 @@ public interface MastershipService
      *
      * @param nodeId the ID of the controller
      * @return a set of device IDs
+     * @deprecated 1.6.0 Goldeneye release.
      */
+    @Deprecated
     Set<DeviceId> getDevicesOf(NodeId nodeId);
 
 }

@@ -843,8 +843,9 @@ public class DistributedFlowRuleStore
             }
             try {
                 // determine the set of devices that we need to backup during this run.
-                Set<DeviceId> devicesToBackup = mastershipService.getDevicesOf(local)
+                Set<DeviceId> devicesToBackup = flowEntries.keySet()
                             .stream()
+                            .filter(mastershipService::isLocalMaster)
                             .filter(deviceId -> {
                                 Long lastBackupTime = lastBackupTimes.get(deviceId);
                                 Long lastUpdateTime = lastUpdateTimes.get(deviceId);