When I did `rake test:bok_choy:setup` I got the following error:
```
echo 'flush_all' | nc localhost 11211
rake aborted!
Command failed with status (1): [echo 'flush_all' | nc localhost 11211...]
edx-platform/rakelib/bok_choy.rake:92:in `block (2 levels) in <top (required)>'
Tasks: TOP => test:bok_choy:setup
```