Introduced new field FlowPathType to the Flow Path.
The initial set of valid values are:

    FP_TYPE_SHORTEST_PATH,              // Shortest path flow
    FP_TYPE_EXPLICIT_PATH               // Flow path with explicit flow entries

For now, the type field is not used (explicitly) yet.
diff --git a/src/main/java/net/onrc/onos/ofcontroller/util/serializers/KryoFactory.java b/src/main/java/net/onrc/onos/ofcontroller/util/serializers/KryoFactory.java
index 507cb99..45a43bf 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/util/serializers/KryoFactory.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/util/serializers/KryoFactory.java
@@ -113,6 +113,7 @@
 	kryo.register(FlowId.class);
 	kryo.register(FlowPath.class);
 	kryo.register(FlowPathFlags.class);
+	kryo.register(FlowPathType.class);
 	kryo.register(IPv4.class);
 	kryo.register(IPv4Net.class);
 	kryo.register(IPv6.class);