patch applied (cabal): look in odir for source and .hs files, not buildDir lbi

[Duncan Coutts]

Mon Sep 17 07:50:30 PDT 2007  Duncan Coutts <duncan at haskell.org>
  * look in odir for source and .hs files, not buildDir lbi
  odir = buildDir lbi for the lib case, which is why it worked most of the time
  in testing but in the exe case it's a different dir.

    M ./Distribution/Simple/GHC.hs -2 +2