Can't set super admin status if network admin email address is set first

[vegasgeek]

(While testing out what I think may be a different bug, I ran in to this)

WordPress Version: 3.1 multisite

While logged in as a super admin, I went to Network Admin -> Settings and set the Network Admin Email address to match the address of an existing user on the site who was not currently granted Super Admin privileges. Then went to Network Admin -> Users, the user who has the matching email address is NOT listed as a Super Admin (I didn't expect it would be). When I clicked edit on that user, I am unable to set him as a Super Admin because it's showing me the "Super admin privileges cannot be removed because this user has the network admin email." message instead.

I tried logging in with the second account and I am not able to see the Network Admin menu options (as expected).

Yes, I realize this is a dumb order to do things in and it's not something I would normally do had I not been testing for some other weird issue I'm seeing.

It's definitely an edge case, might not be worth fixing, since there's been some discussion about removing network admin email option. But I attached a patch nevertheless.