bug#42298: Nonexistent Git commit referenced from current Guix package

[Leo Famulari]

The current Guix package points to a Git commit that does not exist,
which breaks the ability to build the package.

The current package version is '1.1.0-16.d3eee3c'.

That commit d3eee3c [0] is the commit that updated the Guix package
previously, to '1.1.0-15.03deb1e'.

However, there is no commit 03deb1e [1].

I'm not sure exactly which contexts will hit this bug, but somebody on
IRC had trouble:

http://logs.guix.gnu.org/guix/2020-07-09.log#232819

Specifically, while trying to build

'/gnu/store/igf09dzbik8id1bh9f0lahib6716fk81-guix-1.1.0-15.03deb1e-checkout',

... it failed with:

"fatal: reference is not a tree: 03deb1e891b8a8b21888e5e047017fd6a3ea7a5f".

[0]
https://git.savannah.gnu.org/cgit/guix.git/commit/?id=d3eee3c0643a20ba06941ba45d9d27146a8b634d

[1]
https://git.savannah.gnu.org/cgit/guix.git/commit/?id=03deb1e