Failed compilation due to old hspec dependency

Hi,
I had a fairly recent hspec in my system, and as such I could not compile this.
This fix is quite simple.

By the way, I am a strong user of hlint + syntastic (vim). To avoid warnings due to 'redundant do' in tests, would you opose a Hlint directive:

{-# ANN spec ("HLint: ignore Redundant do"::String) #-}

Cheers