New CLA form
Fix exchange client leak when queries are abandoned

The query purger in StatementResource wasn't calling close() on query objects when purging
them from the list of active queries. As a result, abandonded queries would result
in StatementResource leaking an exchange client
Update to airbase 19

This updates Jetty to 9.1.4, which we hope will fix https://github.com/facebook/presto/issues/1138