onedrive: fix nil pointer error when uploading small files

Before this fix when uploading a single part file, if the
o.fetchAndUpdateMetadata() call failed rclone would call
o.setMetaData() with a nil info which caused a crash.

This fixes the problem by returning the error from
o.fetchAndUpdateMetadata() explicitly.

See: https://forum.rclone.org/t/serve-webdav-is-crashing-fatal-error-sync-unlock-of-unlocked-mutex/46300

backend/onedrive/onedrive.go

@@ -2538,6 +2538,9 @@ func (o *Object) uploadSinglepart(ctx context.Context, in io.Reader, src fs.Obje
 	}
 	// Set the mod time now and read metadata
 	info, err = o.fs.fetchAndUpdateMetadata(ctx, src, options, o)
+	if err != nil {
+		return nil, fmt.Errorf("failed to fetch and update metadata: %w", err)
+	}
 	return info, o.setMetaData(info)
 }