[Lithium redesign] some TTL flows (Dec_TTL, Set_MPLS_TTL, Dec_MPLS_TTL) causing NPE and not sent to switch

flow services CI tests have at least three failures because of this:
https://jenkins.opendaylight.org/releng/view/openflowplugin/job/openflowplugin-csit-1node-cds-flow-services-lithium-redesign-only-master/

these tests pass in the helium based tests:
https://jenkins.opendaylight.org/releng/view/openflowplugin/job/openflowplugin-csit-1node-cds-flow-services-only-master/

The short of it is that pushing a flow for TTL decrement, MPLS TTL decrement, or Set MPLS TTL will result in a similar
exception for a NullPointerException:

2015-05-05 16:03:17,474 | ERROR | lt-dispatcher-25 | DataTreeChangeListenerActor | 179 - org.opendaylight.controller.sal-distributed-datastore - 1.2.0.SNAPSHOT | Error notifying listener org.opendaylight.controller.md.sal.binding.impl.BindingDOMDataTreeChangeListenerAdapter@1045caf5
java.lang.NullPointerException
at org.opendaylight.openflowplugin.impl.registry.flow.FlowHashFactory$FlowHashDto.<init>(FlowHashFactory.java:51)[195:org.opendaylight.openflowplugin.impl:0.1.0.SNAPSHOT]

The flow is also not sent to the switch (as I guess could be expected)

The exceptions seem similar, but a separate comment for each flow mod XML and exception trace is added.