minor role relinquishment fix

Change-Id: I8fb2d65795b6bba6c0838c5efcf17d6f6528ea65
diff --git a/core/net/src/main/java/org/onlab/onos/net/device/impl/DeviceManager.java b/core/net/src/main/java/org/onlab/onos/net/device/impl/DeviceManager.java
index a8d63c1..8cde5a3 100644
--- a/core/net/src/main/java/org/onlab/onos/net/device/impl/DeviceManager.java
+++ b/core/net/src/main/java/org/onlab/onos/net/device/impl/DeviceManager.java
@@ -257,6 +257,8 @@
             // temporarily request for Master Role and mark offline.
             if (!mastershipService.getLocalRole(deviceId).equals(MastershipRole.MASTER)) {
                 log.debug("Device {} disconnected, but I am not the master", deviceId);
+                //let go of any role anyways
+                mastershipService.relinquishMastership(deviceId);
                 return;
             }
             DeviceEvent event = store.markOffline(deviceId);