bug#34149: guix refresh -u is broken

[Andreas Enge <andreas@enge.fr>]

Hello!

Unless I mis-remember how the command works, there seems to be a problem
with "guix refresh -u":

$ ./pre-inst-env guix refresh -u python-cysignals
Backtrace:
          14 (apply-smob/1 #<catch-closure 17b4b80>)
In ice-9/boot-9.scm:
    705:2 13 (call-with-prompt _ _ #<procedure default-prompt-handle…>)
In ice-9/eval.scm:
    619:8 12 (_ #(#(#<directory (guile-user) 186d140>)))
In guix/ui.scm:
  1639:12 11 (run-guix-command _ . _)
In ice-9/boot-9.scm:
    829:9 10 (catch _ _ #<procedure 7fd0d71109b0 at guix/ui.scm:617…> …)
    829:9  9 (catch _ _ #<procedure 7fd0d71109c8 at guix/ui.scm:735…> …)
In guix/scripts/refresh.scm:
    513:8  8 (_)
In guix/store.scm:
  1693:24  7 (run-with-store _ _ #:guile-for-build _ #:system _ # _)
In guix/scripts/refresh.scm:
   531:16  6 (_ _)
In srfi/srfi-1.scm:
    640:9  5 (for-each #<procedure 2269ba0 at guix/scripts/refresh.…> …)
In guix/scripts/refresh.scm:
   301:20  4 (update-package #<build-daemon 256.99 1d40e60> #<packa…> …)
In guix/upstream.scm:
   374:22  3 (package-update #<build-daemon 256.99 1d40e60> _ _ # _)
   302:17  2 (download-tarball #<build-daemon 256.99 1d40e60> #f #f # …)
In guix/download.scm:
   568:55  1 (download-to-store #<build-daemon 256.99 1d40e60> #f _ # …)
In unknown file:
           0 (basename #f #<undefined>)

ERROR: In procedure basename:
In procedure scm_to_utf8_stringn: Wrong type argument in position 1 (expecting string): #f


Andreas