Assert on QXL_INTERRUPT_ERROR
Assert on QXL_INTERRUPT_ERROR

When qemu qxl device reaches a guest bug, it might set the
QXL_INTERRUPT_ERROR interrupt flag, and stops processing guest
commands. Therefore, it makes sense to check that flag in the guest and
quit, instead of running in infinite loop in X and consuming CPU.

Related to:
https://bugzilla.redhat.com/show_bug.cgi?id=1151559

fgouget/xf86-video-qxl,fgouget/xf86-video-qxl,fgouget/xf86-video-qxl,fgouget/xf86-video-qxl