Patch beanstalkd collector

'version', 'id', and 'hostname' are not statistics and can be ignored.

See the protocol for a full list of outputs, and their description:

https://github.com/kr/beanstalkd/blob/master/doc/protocol.txt
Merge pull request #659 from MichaelDoyle/patch_beanstalkd_collector

Patch beanstalkd collector