bug#30618: Cuirass dies with locked database

[Andreas Enge <andreas@enge.fr>]

Hello,

one of my latest cuirass runs ended in this:

...
In ice-9/boot-9.scm:
    705:2 12 (call-with-prompt _ _ #<procedure 191f060 at ice-9/eval…>)
    705:2 11 (call-with-prompt _ _ #<procedure 19233e0 at ice-9/eval…>)
In ice-9/eval.scm:
    619:8 10 (_ #(#(#<directory (guile-user) 131d140> #<variable…> …)))
In srfi/srfi-1.scm:
    640:9  9 (for-each #<procedure process (spec)> (((#:name . #) …)))
In cuirass/base.scm:
   576:15  8 (process ((#:name . "guix") (#:url . "https://git.s…") …))
In cuirass/database.scm:
    68:18  7 (%sqlite-exec _ _ . _)
In ice-9/eval.scm:
   293:34  6 (_ #(#(#<directory (sqlite3) 1358820> #<<sqlite-stm…> …)))
    619:8  5 (_ #(#(#(#(#<directory (sqlite3) 1358820> #<…>) #) 5) 5))
In ice-9/boot-9.scm:
   751:25  4 (dispatch-exception 0 sqlite-error (#f 5 "database is…"))
In cuirass/utils.scm:
    115:8  3 (_ _ #f 5 "database is locked")
In ice-9/boot-9.scm:
    829:9  2 (catch #t #<procedure 91c0f00 at cuirass/utils.scm:115…> …)
In cuirass/utils.scm:
   116:22  1 (_)
In unknown file:
           0 (make-stack #t)
ERROR: In procedure make-stack:
Throw to key `sqlite-error' with args `(#f 5 "database is locked")'.

This is probably not dramatic when running it as a service, since then
it will be respawned some time later, but it should be caught in the code.

Andreas