cabal-install-ghc74 fixes

[Andres Löh]

Hi.

As Ben said, cabal-install-0.14.0 should just work with ghc-7.4.1. The
cabal-install-ghc74 package is "unofficial".

Cheers,
  Andres

-- 
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com