[ONOS-2808] Properly deserialzes NDP packets without options

In addition, add following cases into NDP unit tests:
    - testDeserializeBadInput
    - testDeserializeTruncated (NDP headers only, options skipped)

Change-Id: Ia295a5bd7fcdcc25ac556da7bc2eaab13ad8e3b8
diff --git a/utils/misc/src/main/java/org/onlab/packet/ndp/RouterSolicitation.java b/utils/misc/src/main/java/org/onlab/packet/ndp/RouterSolicitation.java
index 07729df..e279a40 100644
--- a/utils/misc/src/main/java/org/onlab/packet/ndp/RouterSolicitation.java
+++ b/utils/misc/src/main/java/org/onlab/packet/ndp/RouterSolicitation.java
@@ -140,11 +140,13 @@
 
             bb.getInt();
 
-            NeighborDiscoveryOptions options = NeighborDiscoveryOptions.deserializer()
-                    .deserialize(data, bb.position(), bb.limit() - bb.position());
+            if (bb.limit() - bb.position() > 0) {
+                NeighborDiscoveryOptions options = NeighborDiscoveryOptions.deserializer()
+                        .deserialize(data, bb.position(), bb.limit() - bb.position());
 
-            for (NeighborDiscoveryOptions.Option option : options.options()) {
-                routerSolicitation.addOption(option.type(), option.data());
+                for (NeighborDiscoveryOptions.Option option : options.options()) {
+                    routerSolicitation.addOption(option.type(), option.data());
+                }
             }
 
             return routerSolicitation;