COLO: Load VMState into QIOChannelBuffer before restore it

COLO: Load VMState into QIOChannelBuffer before restore it

We should not destroy the state of SVM (Secondary VM) until we receive
the complete data of PVM's state, in case the primary fails in the process
of sending the state, so we cache the VM's state in secondary side before
load it into SVM.

Besides, we should call qemu_system_reset() before load VM state,
which can ensure the data is intact.

Signed-off-by: zhanghailiang <[email protected]>
Signed-off-by: Li Zhijian <[email protected]>
Signed-off-by: Gonglei <[email protected]>
Reviewed-by: Dr. David Alan Gilbert <[email protected]>
Cc: Dr. David Alan Gilbert <[email protected]>
Reviewed-by: Amit Shah <[email protected]>
Signed-off-by: Amit Shah <[email protected]>