Fix submodule name to be consistent with pyserini, minor changes to get it to work

[ronakice]

Rename, change eval/ to eval in the path. Seems to only work for me if I do this

[ronakice]

@rodrigonogueira4 can you try: git submodule update --init --recursive once you clone this branch to verify?

[lintool]

this seems to be consistent with pyserini: https://github.com/castorini/pyserini/blob/master/.gitmodules

[rodrigonogueira4]

@rodrigonogueira4 can you try: git submodule update --init --recursive once you clone this branch to verify?

It worked!

[rodrigonogueira4]

LGTM!