[Distributed] Prevent rebooting from damaging file versions

During system reboots, when FileVersionController is recovered, it will automatically increase its current version number by a small amount to prevent the versions of new files conflict with existing files.

However, if one node in a data group reboots, its file version number will become inconsistent with others, which causes troubles during catch-ups.

So, the maximum version number should be precisely recovered from the existing TsFiles, so as to avoid inconsistency.