contrib/globalsign/mgo: err always nil.

[tttoad]

Fixes #2165

[ajgajg1134]

👋 Thanks for the contribution! One thing I think we should add here is a small unit test to verify this change (and make sure we don't regress later)

[darccio]

@tttoad Can you add a unit test to detect future regressions? Thanks!

[tttoad]

Sorry, I didn't notice the your replies(@ajgajg1134). The unit test has been added @darccio .

[darccio]

@tttoad After merging this, we have a question about this library/integration. It's fairly old, last release in 2018, and we are not aware of any alternative. Looking around it seems that juju/mgo is a well maintained fork.

What is the current state of MongoDB drivers from your point of view? Is there any reason to keep using globalsign/mgo?

[tttoad]

@darccio Sorry, I can't give advice... I hardly use mongodb, I just saw the problem and fixed it.

[darccio]

Don't worry. Thanks for the feedback and the fix, @tttoad!