Remove DefaultSetup.hs

My investigation suggests it became unnecessary for the build with revision 21dc5578 (named DefaultSetup.lhs at the time) but has hung around ever since.

Remove DefaultSetup.hs
90610bb9 · Ben Millwood · 1f701e63 · 1f701e63
Commit 90610bb9 authored 12 years ago by Ben Millwood
--- a/Cabal/DefaultSetup.hs
+++ b/Cabal/DefaultSetup.hs
-import Distribution.Simple
-main = defaultMain