gnu: dvdisaster: Use archived source and home page.

* gnu/packages/cdrom.scm (dvdisaster)[source, home-page]:
Use archive.org mirror.

gnu/packages/cdrom.scm

@@ -336,13 +336,15 @@ or @command{xorrisofs} to create ISO 9660 images.")
   (package
     (name "dvdisaster")
     (version "0.79.5")
-    (source (origin
-             (method url-fetch)
-             (uri (string-append "http://dvdisaster.net/downloads/dvdisaster-"
-                                 version ".tar.bz2"))
-             (sha256
-              (base32
-               "0f8gjnia2fxcbmhl8b3qkr5b7idl8m855dw7xw2fnmbqwvcm6k4w"))))
+    (source
+     (origin
+       (method url-fetch)
+       ;; Update this (and update HOME-PAGE) when/if one reappears.
+       (uri (string-append "https://web.archive.org/web/20180428070843/"
+                           "http://dvdisaster.net/downloads/dvdisaster-"
+                           version ".tar.bz2"))
+       (sha256
+        (base32 "0f8gjnia2fxcbmhl8b3qkr5b7idl8m855dw7xw2fnmbqwvcm6k4w"))))
     (build-system gnu-build-system)
     (inputs
      `(("gtk+" ,gtk+-2)))
@@ -384,7 +386,8 @@ or @command{xorrisofs} to create ISO 9660 images.")
                (copy-file "contrib/dvdisaster48.xpm"
                           (string-append datadir "/pixmaps/dvdisaster.xpm"))
                #t))))))
-    (home-page "http://dvdisaster.net/en/index.html")
+    (home-page (string-append "https://web.archive.org/web/20180428070843/"
+                              "http://dvdisaster.net/en/index.html"))
     (synopsis "Error correcting codes for optical media images")
     (description "Optical media (CD,DVD,BD) keep their data only for a
 finite time (typically for many years).  After that time, data loss develops