SONAR suggestion - generic exceptions

Replace uses of generic RuntimeException
with more appropriate unchecked exceptions

Change-Id: If283743c2cf7252b8d280bdb788708ebbe57da9d
diff --git a/protocols/isis/isisio/src/main/java/org/onosproject/isis/io/isispacket/IsisMessageReader.java b/protocols/isis/isisio/src/main/java/org/onosproject/isis/io/isispacket/IsisMessageReader.java
index c1d5f81..09cac03 100644
--- a/protocols/isis/isisio/src/main/java/org/onosproject/isis/io/isispacket/IsisMessageReader.java
+++ b/protocols/isis/isisio/src/main/java/org/onosproject/isis/io/isispacket/IsisMessageReader.java
@@ -105,7 +105,7 @@
      * @return ISIS header
      * @throws Exception
      */
-    private IsisHeader getIsisHeader(ChannelBuffer channelBuffer) throws Exception {
+    private IsisHeader getIsisHeader(ChannelBuffer channelBuffer) {
 
         IsisHeader isisHeader = new IsisHeader();
         isisHeader.setIrpDiscriminator(channelBuffer.readByte());