Fix backward compatibility breakage in FileSystemWrapper (#9156)

Summary:
Implement the Name() method in FileSystemWrapper, since https://github.com/facebook/rocksdb/issues/8649 removed it and it can cause compilation failures. We can deprecate it in RocksDB 7.0.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9156

Reviewed By: riversand963

Differential Revision: D32363977

Pulled By: anand1976

fbshipit-source-id: 1e5a2fec2ab0649255720d89abf5bac26bb64ded

include/rocksdb/file_system.h

@@ -1193,6 +1193,10 @@ class FileSystemWrapper : public FileSystem {
   explicit FileSystemWrapper(const std::shared_ptr<FileSystem>& t);
   ~FileSystemWrapper() override {}
 
+  // Deprecated. Will be removed in a major release. Derived classes
+  // should implement this method.
+  const char* Name() const override { return target_->Name(); }
+
   // Return the target to which this Env forwards all calls
   FileSystem* target() const { return target_.get(); }