Fixed bug for ghc < 6.3 where call to ghc-pkg during configure step
was unconditional.  Now only call ghc-pkg to get versioned
dependencies if >= 6.3. revived buildDepToDep as setDepByVersion,
which sets the exact version number if supplied by the package
description in any case where we can't query the HC-pkg system.

minor fix to withHooks test for hugs