Prevent IntegrityError on repeated reset of journalist password

[rmol]

Status

Ready for review

Description of Changes

Fixes #5617.

Instead of breaking down and making everyone uncomfortable when encountering IntegrityError while revoking a journalist's two-factor token during a password reset, roll with it, take it in stride, demonstrating resilience, class, even aplomb.

Testing

Follow the STR in #5617 on develop. Then git checkout -b fix-5617 origin/fix-5617 and repeat. You should now be able to reset a password for the rest of your days error-free, if that seems a good alternative to whatever else 2020 is handing you.

Deployment

It's probably fine. It's better than it was, anyway. With the new error handling in place, the admin doesn't encounter an error, the journalist gets a new password, everyone's happy.

Checklist

If you made changes to the server application code:

• Linting (make lint) and tests (make test) pass in the development container

If you made non-trivial code changes:

• I have written a test plan and validated it for this PR

Choose one of the following:

• I have opened a PR in the docs repo for these changes, or will do so later
• I would appreciate help with the documentation
• These changes do not require documentation

[kushaldas]

The code diff looks okay, but I could not reproduce the original error.

I kept clicking reset password again and again.

[rmol]

And you were on current develop when you tried, and had logged in at least once as dellsberg?

[kushaldas]

And you were on current develop when you tried, and had logged in at least once as dellsberg?

Yes, and I was still logged on as dellsberg from another browser window.

[eloquence]

As I noted on the issue, I was able to reproduce. Can confirm that this PR resolves the issue; code changes make sense to me.

[kushaldas]

@eloquence confirmed that the patch solves the problem. I did a visual inspection and the code looks okay. CI is green. Approved.