can't reclaim team ownership if owner resets account

STEPS TO REPRODUCE
====================
1. User creates team
2. User adds admins
3. User resets account
4. Email is generated to admins telling them that the user was "kicked out" and is "cryptographically" different but suggests adding them back

EXPECTED RESULTS
==================
You can just follow the instructions to add the user back.

ACTUAL RESULTS
================
* Cannot add user back, either with suggested `keybase team add-member` or under the "Invites" tab in the team (the user had made a request).
* CLI error: `▶ ERROR cannot post link (precheck): appending 6->7: non-owner cannot demote owners`
* UI error: `user`*`"username"`*`is not a member of team`*`"teamname"`*
* Admins cannot add owners.
* Admins cannot demote owners.
* Admins cannot remove owners.

AFFECTED VERSIONS
===================
* Android 1.0.34-20171027214850+c5ade4b91
* Ubuntu 1.0.36-20171122003226.f68b10ef8

I'm posting this on behalf of @vikingredwolf who is the user affected. I'm one of the other admins on a team we're both in, or not, depending on how you interpret the above. ;)

Start by reproducing the issue with `keybase team add-member` and the team's Invites tab, following the listed account-reset steps. No source files or tests are named, so trace the team ownership and member-add paths from those entry points. Done means admins can reclaim the reset owner's membership and manage owner roles without the reported errors.

Written by the indexing model from the issue text.