Use grub workaround repo for F39 Server images

Inexplicably, the grub issue has somehow started affecting F39
server images. Even though neither grub2 nor xfsprogs changed
at all in F39. I can't explain it, but it's nearly midnight and
I don't want to wake up to a wall of failed tests, so we're
trying this. The repo has a build of grub2 with the patch put
back, just like in Rawhide.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

server-39.ks

@@ -0,0 +1,18 @@
+bootloader --location=mbr
+network --bootproto=dhcp
+url --mirrorlist=https://mirrors.fedoraproject.org/mirrorlist?repo=fedora-$releasever&arch=$basearch
+repo --name=updates --mirrorlist=https://mirrors.fedoraproject.org/mirrorlist?repo=updates-released-f$releasever&arch=$basearch
+repo --name=grubxfs-repo --baseurl=https://adamwill.fedorapeople.org/grubxfs-repo/$releasever/$basearch
+lang en_US.UTF-8
+keyboard us
+timezone --utc America/New_York
+clearpart --all
+autopart
+rootpw weakpassword
+user --name=test --password=weakpassword --plaintext --groups wheel
+poweroff
+
+%packages
+@^server-product-environment
+plymouth-system-theme
+%end