Fix virtio-gpu + virgl support by cherry-picking upstream commits

virt-manager in current sid still creates new VMs with QXL graphics by default,
so this bug only affects users who opt in for virtio-gpu + 3D acceleration.
Still, the option for virtio-gpu + 3D acceleration is offered in the
virt-manager GUI, so having it broken by default is an important problem.

These are upstream commits:
f2cbb94eabdd5e3422c45b1afa48eb4c951c09e0
00fbb9e51678f76effa2d20e78a9be861ad5f484
27a9ebf28183cb3c3c784fcab622e67e978eb3dc
d85e8e400b48f1b4c1dfbf438dda83cd959eacf7
fb01e1a44daea773cd53f275cad6f031506c20db

Closes: #916587