Add Verbose-level logging of the haddock response-file

contents. Prior to the response file code, all of these
details of the command line for haddock would have been
logged (with level == Verbose), so this corrects an oversight
and brings the information in the logging back to what it
used to be for cabal's haddock invocations.

* Cabal/Distribution/Simple/Haddock.hs
  * Restore the logging of the entire command line used when
    invoking haddock to what it used to be prior to adding
    the response-file creation.