Fix GHC backwards compatibility problem in test

cabal-testsuite/PackageTests/NewSdist/ManyDataFiles/many-data-files.test.hs

 import Test.Cabal.Prelude
+
+import Control.Applicative ((<$>))
 import System.Directory ( createDirectoryIfMissing )
 import qualified Data.ByteString.Char8 as BS