ivs: negotiate as OF 1.4
OVSDriver: use ethernet port stats property for OF 1.4
OVSDriver: use ethernet port desc property for OF 1.4
OVSDriver: set VLAN CFI bit in packet-in match for OF 1.4
Merge into master from pull request #226:
OF 1.4 support (https://github.com/floodlight/ivs/pull/226)