haskell-src-exts: disable 'doCheck' because of test suite build errors

Test/Runner.hs:5:8:
    Could not find module `Language.Haskell.Exts.Annotated'
    Use -v to see a list of the files searched for.
Setup: Pattern match failure in do expression at Setup.hs:6:5-15
haskell-filestore: cosmetic