Stop xmllint scrollkeeper-omf.dtd fetch failure breaking CI tests
Here's the fix for this.
As noted before, I tested the fix by making scrollkeeper.sourceforge.net point to 127.0.0.1 in /etc/hosts in the Docker CI image and confirming this broke xmllint fetching of the remote scrollkeeper-omf.dtd file. Then applied the fix. See my branch external-scrollkeeper-devel1 at Mike Fleetwood / gparted.