Small fix.

@johnsca one more quick question about relational context.py.

It's about this [line](https://github.com/cf-charmers/cloudfoundry/blob/c97c4a622b08a486c08d66bccfc19d27fa3d5252/charmhelpers/core/services/helpers.py#L48). As far as I know `bool([])` is already `False` in python, so you don't need to do `len(...) > 0` there. 

Once you want to be sure that `ready` is a boolean I think it's better to use `bool()` or `!!` casting.