Catch up RPC context fixes on NEC OpenFlow plugin

Fixes bug 1099179

Change-Id: Ib61081c3aaed8770906dd57874c45358b0418c3f
NEC OpenFlow plugin supports L3 agent RPC

Fixes bug 1099879

Change-Id: Icbe1d686fea2f821e55c4a25916361dbfe9ad380
Merge "Catch up RPC context fixes on NEC OpenFlow plugin"
Merge "NEC OpenFlow plugin supports L3 agent RPC"