libvirt_bench: Change the post_state to a list of states.

As we can not make sure the state after virsh shutdown, it
is about the performance of your machine at that time, this
patch make the post state work as a list. Add more state in
config file seperated with ','.

Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
libvirt_bench: Wait for ttcp server be ready before we execute ttcp command on guest.

As we need some time to setup the server on host, we will get
some error in current test of libvirt_bench for ttcp.

This patch wait for the server end on host be ready and then
execute ttcp on guest.

Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>