* fix: prevent empty .vif files from ec.decode causing parse errors
When ec.decode copies .vif files from EC shard nodes, if a source node
doesn't have the .vif file, an empty .vif file was created on the target
node. This caused volume.configure.replication to fail with 'proto: syntax
error' when trying to parse the empty file.
This fix:
1. In writeToFile: Remove empty files when no data was written (source
file was not found) to avoid leaving corrupted empty files
2. In MaybeLoadVolumeInfo: Handle empty .vif files gracefully by treating
them as non-existent, allowing the system to create a proper one
Fixes#7666
* refactor: remove redundant dst.Close() and add error logging
Address review feedback:
- Remove redundant dst.Close() call since defer already handles it
- Add error logging for os.Remove() failure
5c27522507