SONAR suggestion - generic exceptions

Replace uses of generic RuntimeException
with more appropriate unchecked exceptions

Change-Id: If283743c2cf7252b8d280bdb788708ebbe57da9d
diff --git a/providers/netconf/device/src/main/java/org/onosproject/provider/netconf/device/impl/NetconfDeviceProvider.java b/providers/netconf/device/src/main/java/org/onosproject/provider/netconf/device/impl/NetconfDeviceProvider.java
index c35682c..99c8ebd 100644
--- a/providers/netconf/device/src/main/java/org/onosproject/provider/netconf/device/impl/NetconfDeviceProvider.java
+++ b/providers/netconf/device/src/main/java/org/onosproject/provider/netconf/device/impl/NetconfDeviceProvider.java
@@ -582,7 +582,7 @@
                 providerService.deviceDisconnected(deviceId);
             }
             deviceKeyAdminService.removeKey(DeviceKeyId.deviceKeyId(deviceId.toString()));
-            throw new RuntimeException(new NetconfException(
+            throw new IllegalStateException(new NetconfException(
                     "Can't connect to NETCONF device " + deviceId, e));
 
         }