patch applied (cabal-install): Swap Either args so it's Either Error Ok

[Duncan Coutts]

Fri May  9 08:20:07 PDT 2008  Duncan Coutts <duncan at haskell.org>
  * Swap Either args so it's Either Error Ok
  Which seems to be the normal convention.

    M ./Hackage/Dependency.hs -14 +12
    M ./Hackage/InstallPlan.hs -3 +3

View patch online:
http://darcs.haskell.org/cabal-install/_darcs/patches/20080509152007-adfee-8b13d88b5938eef6aab43bf66811da3d9278d50a.gz