after migrate, some old host still exist in show hosts result.

[liuyu85cn]

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Describe the bug (required)

https://discuss.nebula-graph.com.cn/t/topic/8183

background : user migrate from cluster A to cluster B.

1. "add host" in cluster A. create some space ....
2. migrate to cluster B, use http replace request.
3. "show hosts" in cluster B.

what he expected is that he only see b1, b2, b3. (for example)
but actually, he also see a1, a2, a3 as offline.

looked like the code. And talked Critial and Pengwei, we add some item in machineTable
but machineTable is not well migrated.

Your Environments (required)

• OS: uname -a
• Compiler: g++ --version or clang++ --version
• CPU: lscpu
• Commit id (e.g. a3ffc7d8)

How To Reproduce(required)

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1. Step 1
2. Step 2
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Expected behavior

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