bug#35190: Hydra unable to new create evaluations of master

[Mark H Weaver <mhw@netris.org>]

Hydra's latest attempt to evaluate 'master' failed.  Here's the tail of
the evaluation log:

--8<---------------cut here---------------start------------->8---
building path(s) `/gnu/store/103icyz4q7crjxbh71k3vbill3kzjm9n-profile'
Backtrace:
           7 (apply-smob/1 #<catch-closure 1f0b300>)
In ice-9/boot-9.scm:
    705:2  6 (call-with-prompt _ _ #<procedure default-prompt-handle?>)
In ice-9/eval.scm:
    619:8  5 (_ #(#(#<directory (guile-user) 1fc4140>)))
In ice-9/command-line.scm:
   181:18  4 (_ #<input: string 2012a10>)
In unknown file:
           3 (eval (apply (module-ref (resolve-interface (?)) #) #) #)
In ice-9/eval.scm:
   293:34  2 (_ #(#(#(#(#<directory (hydra-eval-guile-jobs?>) ?) ?) ?))
    159:9  1 (_ _)
In guix/utils.scm:
    632:8  0 (call-with-temporary-directory _)

guix/utils.scm:632:8: In procedure call-with-temporary-directory:
Throw to key `match-error' with args `("match" "no matching pattern" #<inferior-object #<procedure non-copyleft (uri #:optional comment)>>)'.

Some deprecated features have been used.  Set the environment
variable GUILE_WARN_DEPRECATED to "detailed" and rerun the
program to get more information.  Set it to "no" to suppress
this message.
--8<---------------cut here---------------end--------------->8---

        Mark