Fix drivers completions

[remisalmon]

Fixes #478

The drivers NewCompleter was removed from the handler between v0.18.1 and v0.19.0.
Tested locally, I had to cleanup the dependencies for go to build.

[nineinchnick]

Thanks a lot for working on it! I found that the completer calls were moved from Open to New in 05236d1. We should figure out why, to avoid calling it twice. @kenshaw do you have more context why? Should we revert this one change?

[remisalmon]

Thanks a lot for working on it! I found that the completer calls were moved from Open to New in 05236d1. We should figure out why, to avoid calling it twice. @kenshaw do you have more context why? Should we revert this one change?

I was thinking to also move the drivers.NewCompleter() call to New but New is missing the context that this function needs.
I moved all completer calls back to Open in 2ad11cf to simplify a little but I can revert if you prefer?

[nestor-custodio]

At the risk of coming across like a nag, I think bumping this PR seems warranted given that the issue persists and we've seen 15 releases since the proposed fix was submitted for approval. 😶‍🌫

[stephane-klein]

bump

[remisalmon]

I just tested this patch with the latest master and it still works on my end. Asking for a re review 🤞

[nineinchnick]

This looks redundant. We should leave this in New, and only create the driver's completer here.

[remisalmon]

Reverted that in 14d1f30.

[kenshaw]

@remisalmon Hi, I apologize for not looking at this earlier. Could you squash the commits into a single commit and I'll rebase onto master and backport it to the release-20 branch? Thanks.