patch applied (packages/Cabal): First go at supporting ghc-6.9's ghc-pkg list --simple-output

[Clemens Fruhwirth]

Fri Dec  7 04:31:07 PST 2007  Duncan Coutts <duncan at haskell.org>
  * First go at supporting ghc-6.9's ghc-pkg list --simple-output
  We used to have to parse the human readable output from ghc-pkg list because
  previously it was not possible to specify which package dbs to query.
  Now the behaviour is that you specify exactly which dbs you want and you
  only get those packages listed. For example ghc-pkg list --global lists only
  packages from the global db. So we now use:
  ghc-pkg list --simple-output --global
  ghc-pkg list --simple-output --global --user

    M ./Distribution/Simple/GHC.hs -14 +29