virsh.vcpucount: fix 'guest_option' test case

There was a missing option whether we are running 'guest_option' test
case to properly start a guest agent in the guest.

I've also properly updated the first occurrence of that condition.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Merge pull request #213 from Antique/vcpucount

virsh.vcpucount: fix 'guest_option' test case