Remove AsyncHttpClient references from the http-client README
Remove AsyncHttpClient references from the http-client README

cberner/airlift,cberner/airlift,haozhun/airlift,daququ/airlift,electrum/airlift,airlift/airlift,airlift/airlift,daququ/airlift,zhenyuy-fb/airlift,mono-plane/airlift,electrum/airlift,daququ/airlift,cberner/airlift,mono-plane/airlift,cberner/airlift,johngmyers/airlift,johngmyers/airlift,airlift/airlift,zhenyuy-fb/airlift,haozhun/airlift,zhenyuy-fb/airlift,mono-plane/airlift,dain/airlift,mono-plane/airlift,dain/airlift,johngmyers/airlift,daququ/airlift,haozhun/airlift,airlift/airlift,electrum/airlift,dain/airlift,dain/airlift,zhenyuy-fb/airlift,electrum/airlift,haozhun/airlift,johngmyers/airlift