[#69996486] Make collectd collect disk stats.
[#69996486] Make collectd collect disk stats.

Just load the df and disk plugins instead of using the custom
configuration classes for them because we dont need to configure them.

boffbowsh/ci-puppet,boffbowsh/ci-puppet,alphagov/ci-puppet,alphagov/ci-puppet,alphagov/ci-puppet,alphagov/ci-puppet,boffbowsh/ci-puppet,boffbowsh/ci-puppet