'Update My Key' fails with "cannot have 2 primary keys"

I've added a subkey, revoked another one, and removed my secret key (I store it on secure media). 'Update My Key (I edited it elsewhere)' now reports: "cannot have 2 primary keys"

The fingerprint of my key is unchanged:

```
$ keybase id mayo
public key fingerprint: 50FE C3A3 64B5 9BEE 734D 0E9B 56A3 789C ED4D 2DD7
$ gpg2 --fingerprint ED4D2DD7
pub 4096R/ED4D2DD7 2015-03-19
Key fingerprint = 50FE C3A3 64B5 9BEE 734D 0E9B 56A3 789C ED4D 2DD7
```

Start by reproducing the 'Update My Key' flow after adding a subkey, revoking another, and removing the secret key, using the unchanged fingerprint and the gpg2 command shown in the report. Trace how the update handles primary keys and subkeys; done means the key updates without reporting that it has two primary keys.

Written by the indexing model from the issue text.