bug#43940: The "channel-instances->manifest" test fails

[Maxim Cournoyer]

Hello,

The error has to do with channel-instances->manifest now trying to
url-fetch something, which pulls in guile-final which fails to be
resolved.

I've git bisected it and it points to commit
1d4ab335b22a93e01c2eb1eb3e93fc6534157040.

Here's a ,trace output of the culprit, in case it helps.
--8<---------------cut here---------------start------------->8---
trace: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  (url-fetch/executable 
("https://git.savannah.gnu.org/…"; …) …)
trace: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  (default-guile)
trace: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  
(resolve-interface (gnu packages commencement))
trace: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  (_ (gnu 
packages commencement) #t #f #:ensure #f)
trace: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  (_ 
#<procedure 7f7ac11e7d40 at ice-9/boot-9.scm:…)
--8<---------------cut here---------------end--------------->8---

Thanks,

Maxim