What I want in R^5RS

["Guillermo J. Rozas" <jinx@altdorf.ai.mit.edu>]

   From: Guy Steele <gls@Think.COM>
   Date: Tue, 3 Dec 91 13:07:56 EST

      Date: Mon, 2 Dec 91 11:17:12 PST
      From: kend@data.rain.com (Ken Dickey)


      (FILE-EXISTS? <filename-string>) -- returns #t or #f
      (DELETE-FILE <filename-string>) --> unspecified

   Should DELETE-FILE return an indication of success or failure?

I would prefer an error to be signalled if the deletion failed.
OPEN-INPUT-FILE, etc. signal when opening fails, and I think we should
be consistent.