Ref to eenum repo in rebar.config become invalid, can't build

[krant]

https://github.com/ruanpienaar/eenum.git is no more. We need to fork https://github.com/rpt/eenum.git into the FlowForwarding, add "{erl_opts, []}." into eenum/rebar.config and change eenum ref in of_protocol/rebar.config to "https://github.com/FLowForwarding/eenum.git"

[marcsugiyama]

Updated as suggested.