bug#48127: appstream-glib build tests fail

[Jack Hill]

As of Guix 10ecae4503addec38439a01868e641110a548082 appstream-glib builds 
for me, and I was able to sucessfully update my profile and reconfigure my 
system.

It was fixed by Leo Prikler in 90b4890c630637d1eb4711a7a57f610bbf9cfa57
Best,
Jack