Added enforcer pluin to enforce maven 3 and java 6
Added enforcer pluin to enforce maven 3 and java 6

erichwang/airlift,dain/airlift,zhenyuy-fb/airlift,proofpoint/platform,martint/airlift,daququ/airlift,mono-plane/airlift,mono-plane/airlift,zhenyuy-fb/airlift,electrum/airlift,gwittel/platform,dain/airlift,martint/airlift,airlift/airlift,mono-plane/airlift,erichwang/airlift,cberner/airlift,airlift/airlift,johngmyers/platform-rack,daququ/airlift,johngmyers/platform,johngmyers/airlift,johngmyers/platform-rack,johngmyers/platform,haozhun/airlift,zhenyuy-fb/airlift,daququ/airlift,johngmyers/airlift,gwittel/platform,haozhun/airlift,zhenyuy-fb/airlift,johngmyers/airlift,electrum/airlift,airlift/airlift,johngmyers/platform-rack,proofpoint/platform,johngmyers/platform,gwittel/platform,haozhun/airlift,dain/airlift,erichwang/airlift,cberner/airlift,proofpoint/platform,daququ/airlift,airlift/airlift-rack,martint/airlift,airlift/airlift,johngmyers/platform-rack,electrum/airlift,johngmyers/platform-rack,dain/airlift,johngmyers/platform-rack,haozhun/airlift,airlift/airlift-rack,electrum/airlift,johngmyers/airlift,cberner/airlift,mono-plane/airlift,cberner/airlift