<fix>[vm]: touch qmp socket file after snapshots
<fix>[vm]: touch qmp socket file after snapshots

touch qmp file will trigger filesystem event,
it will trigger to qemu refresh write-threshold.

Resolves: ZSTAC-44658

Change-Id: I6f6f6f6a69706267646c687a6d7577706d67786d

zstackio/zstack-utility,zstackio/zstack-utility,zstackio/zstack-utility