no longer need to pass --ghc-pkg to haddock
no longer need to pass --ghc-pkg to haddock

Haddock only runs ghc-pkg if invoked with --use-package, and Cabal no
longer uses that option, as it now gets the arguments for --read-interface
from ghc-pkg directly (cf patch "rejig location of package interfaces
for haddock").


IreneKnapp/Faction,IreneKnapp/Faction