Snapper DBus woes

[raingloom]

Hiya folks.

I'm trying to finish up that Snapper package that Pierre Neidhardt
abandoned and am also running into DBus issues.
Could someone who knows DBus look into it? I really think we should get
this package working on Guix sooner rather than later, because right
now there is no way to protect against an accidental `rm -rf $HOME`
without a full backup.
This is my branch:
https://git.sr.ht/~raingloom/guix-source/tree/raingloom/snapper