Summary:
Update check_format_compatible.sh with 6.15.fb

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7738

Reviewed By: ajkr

Differential Revision: D25307717

Pulled By: ramvadiv

fbshipit-source-id: 49f5c6366e8c8a2ade9697975453c9c65e919f1b