[leo_object_storage][test] API to break a data block in AVS

[mocchira]

In order to test such as #589. (like add_incorrect_data/1 for compaction tests)

-module(leo_object_storage_api).

-ifdef(TEST).
-spec(overwrite_data(Offset, Bin) -> ok | {error, any()} when Offset::pos_integer(), 
                                                              Bin::binary()).
-endif.

[mocchira]

WIP

[yosukehara]

I've confirmed this issue was resolved:

• leo_object_storage_api
  • leo_object_storage_api.erl#L389-L396
• leo_object_storage_server
  • leo_object_storage_server.erl#L316-L317
• leo_object_storage_haystack
  • leo_object_storage_haystack.erl#L53
  • leo_object_storage_haystack.erl#L372-L383