Summary:
Fix the following error while running `make crash_test`
```
Traceback (most recent call last):
File "tools/db_crashtest.py", line 705, in <module>
main()
File "tools/db_crashtest.py", line 696, in main
blackbox_crash_main(args, unknown_args)
File "tools/db_crashtest.py", line 479, in blackbox_crash_main
+ list({'db': dbname}.items())), unknown_args)
File "tools/db_crashtest.py", line 414, in gen_cmd
finalzied_params = finalize_and_sanitize(params)
File "tools/db_crashtest.py", line 331, in finalize_and_sanitize
dest_params.get("user_timestamp_size") > 0):
TypeError: '>' not supported between instances of 'NoneType' and 'int'
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8091
Test Plan: make crash_test
Reviewed By: ltamasi
Differential Revision: D27268276
Pulled By: riversand963
fbshipit-source-id: ed2873b9587ecc51e24abc35ef2bd3d91fb1ed1b