bug#68273: 'guix refresh asio' crashes with a match-error

[Maxim Cournoyer]

Hello,

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$ guix refresh asio

Backtrace:
In ice-9/boot-9.scm:
  1752:10 16 (with-exception-handler _ _ #:unwind? _ # _)
In unknown file:
          15 (apply-smob/0 #<thunk 7f92e279d2a0>)
In ice-9/boot-9.scm:
    724:2 14 (call-with-prompt _ _ #<procedure default-prompt-handle…>)
In ice-9/eval.scm:
    619:8 13 (_ #(#(#<directory (guile-user) 7f92e27a2c80>)))
In guix/ui.scm:
   2324:7 12 (run-guix . _)
  2287:10 11 (run-guix-command _ . _)
In ice-9/boot-9.scm:
  1752:10 10 (with-exception-handler _ _ #:unwind? _ # _)
  1752:10  9 (with-exception-handler _ _ #:unwind? _ # _)
In guix/store.scm:
   661:37  8 (thunk)
In guix/monads.scm:
    576:2  7 (run-with-store #<store-connection 256.99 7f92caad1500> …)
In guix/scripts/refresh.scm:
   657:14  6 (_ _)
In srfi/srfi-1.scm:
    634:9  5 (for-each #<procedure 7f92cdf1e960 at guix/scripts/ref…> …)
In guix/scripts/refresh.scm:
   402:10  4 (check-for-package-update #<<update-spec> package: #<p…> …)
In srfi/srfi-1.scm:
   858:15  3 (any1 #<procedure 7f92cdf1e930 at guix/upstream.scm:25…> …)
In guix/gnu-maintenance.scm:
   882:13  2 (latest-sourceforge-release _ #:version _)
In ice-9/boot-9.scm:
  1685:16  1 (raise-exception _ #:continuable? _)
  1685:16  0 (raise-exception _ #:continuable? _)

ice-9/boot-9.scm:1685:16: In procedure raise-exception:
Throw to key `match-error' with args `("match" "no matching pattern" ())'.
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This case should be handled and do nothing, rather than crash.

-- 
Thanks,
Maxim