Remove redundant wild-card pattern match

(this would otherwise cause a build-failure with `-Werror`)
Treat GHC 7.10 the same as GHC 7.9

...since the current GHC 7.9 is going to become GHC 7.10 real-soon-now anyway
Fixup ghc.mk (follow-up to 1739375eb23342)

This makes the GHC build-system aware of the data-files to be copied
into the bindist (as haddock.cabal doesn't list those anymore)