Remove locks prefix or make it at least configurable

Why do you prefix the lock keys with "/locks/"?
Why is this not mentioned in the API documentation?
Why is this not configurable?

``` python
lock_prefix = '/locks/'
[...]
self.key = lock_prefix + self.name
```

Start at the lock implementation containing the shown lock_prefix and self.key assignments. Decide whether the lock prefix should be removed or exposed as configuration, then document the resulting behavior in the API documentation. Add or update coverage for the chosen behavior before considering the issue done.

Written by the indexing model from the issue text.