meta: miss sustained nodes in LoadMeta

[jiefenghuang]

What happened: sustained nodes not loaded from backup

What you expected to happen: sustained nodes loaded

How to reproduce it (as minimally and precisely as possible): open some files, delete them and dump

Anything else we need to know?

Environment:

• JuiceFS version (use juicefs --version) or Hadoop Java SDK version: main branch
• Cloud provider or hardware configuration running JuiceFS:
• OS (e.g cat /etc/os-release):
• Kernel (e.g. uname -a):
• Object storage (cloud provider and region, or self maintained):
• Metadata engine info (version, cloud provider managed or self maintained):
• Network connectivity (JuiceFS to metadata engine, JuiceFS to object storage):
• Others:

[jiefenghuang]

Since the edge has been deleted, the sustained inode will not be output in "FSTree" when dumping in JSON format. so it is not needed to load and clean.