fix lxc-wait waiting forever for FREEZING, FROZEN, THAWED states

fix lxc-wait waiting forever for FREEZING, FROZEN, THAWED states

These states are kept by the kernel in the freezer.state cgroup item, and
are never set in handler->state with lxc_set_state(). If lxc transitions
a container to/from the freezer after an lxc-wait for one of the above
states has already started, the lxc-wait will never see the new state. This
change has lxc send the new state to the lxc-monitor socket.

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>