SONAR suggestion - generic exceptions

Replace uses of generic RuntimeException
with more appropriate unchecked exceptions

Change-Id: If283743c2cf7252b8d280bdb788708ebbe57da9d
diff --git a/providers/openflow/device/src/main/java/org/onosproject/provider/of/device/impl/OpenFlowDeviceProvider.java b/providers/openflow/device/src/main/java/org/onosproject/provider/of/device/impl/OpenFlowDeviceProvider.java
index b489c52..66ded21 100644
--- a/providers/openflow/device/src/main/java/org/onosproject/provider/of/device/impl/OpenFlowDeviceProvider.java
+++ b/providers/openflow/device/src/main/java/org/onosproject/provider/of/device/impl/OpenFlowDeviceProvider.java
@@ -1004,7 +1004,7 @@
                     sigType = CltSignalType.CLT_100GBE;
                     break;
                 default:
-                    throw new RuntimeException("Un recognize OduClt speed: " + portSpeedInMbps.toString());
+                    throw new IllegalArgumentException("Un recognize OduClt speed: " + portSpeedInMbps.toString());
             }
 
             SparseAnnotations annotations = buildOduCltAnnotation(port);