kvm tools: Respect paused status in ./lkvm list

kvm tools: Respect paused status in ./lkvm list

'./lkvm list' does not give the correct vm status if the vm is paused
currently.

This patch fixes this by using KVM_IPC_VMSTATE IPC cmd to query the vm
status.

Suppose the guest is paused by ./lkvm pause:

Before:

asias@hj$ ./lkvm list
   PID NAME                 STATE
------------------------------------
 3036 guest-3036           running
      default              shut off

After:

asias@hj$ ./lkvm list
   PID NAME                 STATE
------------------------------------
 3036 guest-3036           paused
      default              shut off

Signed-off-by: Asias He <asias.hejun@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>