tests/qemu-iotests/235: Allow fallback to tcg

iotest 235 currently only works with KVM - this is bad for systems where
it is not available, e.g. CI pipelines. The test also works when using
"tcg" as accelerator, so we can simply add that to the list of accelerators,
too.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

tests/qemu-iotests/235

@@ -49,7 +49,7 @@ qemu_img_create('-f', iotests.imgfmt, '-o', 'preallocation=metadata', disk,
                 str(size))
 
 vm = QEMUMachine(iotests.qemu_prog)
-vm.add_args('-machine', 'accel=kvm')
+vm.add_args('-machine', 'accel=kvm:tcg')
 if iotests.qemu_default_machine == 's390-ccw-virtio':
         vm.add_args('-no-shutdown')
 vm.add_args('-drive', 'id=src,file=' + disk)