Remove duplicate function getOpCode().

- getOpCode() does NOT match the camel casing of the class name ArpOpcode
- getOpcode() match the camel casing of the class name ArpOpcode
- These 2 functions do the same thing
- getOpCode() (the one to be removed) does not seem to be used in Floodlight
- We cannot be sure that it is not used anywhere else though
Merge into master from pull request #128:
java_gen: add workaround for OF1.0 untagged value in OF1.3 VlanVid to OFVlanVidMatch.java (https://github.com/floodlight/loxigen/pull/128)
Merge branch 'master' of github.com:floodlight/loxigen
Merge into master from pull request #131:
Remove duplicate function getOpCode(). (https://github.com/floodlight/loxigen/pull/131)
loxi_ir: minor fix for compability with python <2.7.3

In python <2.7.3, vars() of a namedtuple returns a TypeError.
Using _asdict instead.
Merge branch 'master' of github.com:floodlight/loxigen