'domaincapstest' is currently skipping RISC-V tests. Let's enable it.
The decision of enabling the "virt" machine is based on the idea that
this is the most used QEMU RISC-V machine in the community and it's the
most likely to be widely supported in the long run.
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>