Comment 4 for bug 1465444

I think I found the issue. I'm not 100% sure but I think it's possible that the logic that determines how many excess keys are in the repository doesn't account for negative slices in the list [0].

Here is a paste of what I was playing with [1]. I'm going to tinker with that logic.

[0] https://github.com/openstack/keystone/blob/1ce6a87738be1d6694c3feaf048547f7c58a1604/keystone/token/providers/fernet/utils.py#L212
[1] http://cdn.pasteraw.com/bsaknota9ex7cz7pua1c3koaezagjh2