patch applied (cabal): Remove some now-unecessary cleaning that causes problems for haskell-src

[Duncan Coutts]

Thu Sep 20 13:32:57 PDT 2007  Ian Lynagh <igloo at earth.li>
  * Remove some now-unecessary cleaning that causes problems for haskell-src
  The code that removes .hs files in the source tree generated from .y files
  had a comment:
      XXX: This is actually no longer necessary, but we keep it, so that
      clean works correctly on packages built with an older version of Cabal
  This was causing problems for source distributions that include such
  generated files (including haskell-src in extralibs).

    M ./Distribution/Simple.hs -5 +1