passing correct nameid after shib3 upgrade

[Cantor, Scott]

> I removed all the NameIDFormat lines in the metadata except for the one I
> wanted and it’s being passed now.  Thank you all!

I added a note about this to the UpgradingFromV2 page now that I understand what people are running into, if you had a second to review it and see if it would have helped or needs more clarification, I'd appreciate it.

-- Scott