changed to RSpec's expect syntax

I decided to change clearance to expect syntax for a project I was working on.  If, you want what I did, great!  If, not, you can just close this.

Please note, I have not done a poll request before.  If I have done it incorrectly, I apologize.
No, 2.99 is fine for now. We can do 3.0 in a later commit.

But the same question applies. I think you need to pass a block: https://www.relishapp.com/rspec/rspec-expectations/v/2-0/docs/matchers/expect-error