Forwarding's doDropFlow() changed to not base Match on OFPacketIn, which it...

Forwarding's doDropFlow() changed to not base Match on OFPacketIn, which it shouldn't in the first place. We need to first deserialize the packet and use its header attributes. TODO: How much is too much to match on? Sometimes we want a very specific match by default. Other times, we don't. The former creates a larger flow table, while the latter might inadvertently match packets that we don't intend to. Perhaps this should be a user-configurable option? Such as net.floodlightcontroller.Forwarding.matchLayer=L2, L3, or L4?