virttest.qemu_vm: add virtio-rng-device support

Signed-off-by: Xu Tian <xutian@redhat.com>
virttest.test_setup: add setup egp.pl on localhost support

Signed-off-by: Xu Tian <xutian@redhat.com>
shared.deps: add egd server source code

Signed-off-by: Xu Tian <xutian@redhat.com>
shared.cfg: add cfg to no virtio-rng device by default

Signed-off-by: Xu Tian <xutian@redhat.com>
Merge pull request #1817 from xutian/add_virtio_rng_support

Add virtio rng device support