[Users] GRHydro cleanup

[Erik Schnetter]

I created a pull request for a small cleanup of the build requirements
of GRHydro.

(1) Was anybody notified about this new pull request?
(2) Can (should?) this be integrated with TRAC? Or should we switch to
using Bitbucket's issue tracker?
(3) Could someone have a look and then "push the button"? I'm curious
what happens.

-erik

-- 
Erik Schnetter <schnetter at cct.lsu.edu>
http://www.perimeterinstitute.ca/personal/eschnetter/