Refactor exception handling in the OSPF protocol

- removed unnecessary throws of Exception from methods
- converted throws of generic Exception to specific OspfParseException

Change-Id: I9d07167d92f221a234e9eba4c6082deb165afc0b
diff --git a/protocols/ospf/protocol/src/main/java/org/onosproject/ospf/protocol/lsa/tlvtypes/RouterTlv.java b/protocols/ospf/protocol/src/main/java/org/onosproject/ospf/protocol/lsa/tlvtypes/RouterTlv.java
index 83bf918..8ac443b 100644
--- a/protocols/ospf/protocol/src/main/java/org/onosproject/ospf/protocol/lsa/tlvtypes/RouterTlv.java
+++ b/protocols/ospf/protocol/src/main/java/org/onosproject/ospf/protocol/lsa/tlvtypes/RouterTlv.java
@@ -71,9 +71,9 @@
      * Reads bytes from channel buffer .
      *
      * @param channelBuffer channel buffer instance
-     * @throws Exception might throws exception while parsing buffer
+     * @throws OspfParseException might throws exception while parsing buffer
      */
-    public void readFrom(ChannelBuffer channelBuffer) throws Exception {
+    public void readFrom(ChannelBuffer channelBuffer) throws OspfParseException {
         try {
             byte[] tempByteArray = new byte[OspfUtil.FOUR_BYTES];
             channelBuffer.readBytes(tempByteArray, 0, OspfUtil.FOUR_BYTES);