Update to redis-rb v3.3.2, includes IO::WaitWritable bug
Update to redis-rb v3.3.2, includes IO::WaitWritable bug

The newer version will correctly perform async I/O which should hopefully
make our redis client in API more stable.

https://github.com/redis/redis-rb/commit/cf9d7b376a2949759638ba51619a6d825a04ac59

travis-ci/travis-api,travis-ci/travis-api,travis-ci/travis-api