Nifty load tester fixes (and move to libthrift-0.9.0)

Fixes for nifty load test server

This also moves from libthrift-0.8.0 to libthrift-0.9.0, included in this pull because unexpected exception handling and oneway (which can be stressed with this diff) don't work right on thrift-0.8.0: oneway methods were sending a response (there was no code in the processor to skip this for oneway methods), and unexpected exceptions aren't handled by the processor so (in nifty) they were causing a netty channel exception.