patch applied (cabal): Install haddock interface only when generated

Mon Jun 9 12:02:51 PDT 2008 Duncan Coutts * Install haddock interface only when generated This is actually Andrea Rossato's patch but it didn't merge cleanly due to more recent changes. Fixes ticket #250. M ./Distribution/Simple/Install.hs -4 +10 View patch online: http://darcs.haskell.org/cabal/_darcs/patches/20080609190251-adfee-bc6a8e25c...