Tracking user does not add his pubkey to my keychain

``` console
$ keybase --version
0.8.12
$ keybase track kian
info: ...all remote checks are up-to-date
✔ "kianmohageri" on twitter: https://twitter.com/kianmohageri/status/471432408676712448 (you've recently OK'ed this proof)
✔ "kian" on github: https://gist.github.com/95bc618195778b96c0fe (you've recently OK'ed this proof)
✔ admin of kianmohageri.com via HTTP: http://kianmohageri.com/keybase.txt (you've recently OK'ed this proof)
info: ✔ Wrote tracking info to local database
info: Success!
$ gpg -k
/home/phil/.gnupg/pubring.gpg
-----------------------------
pub 3072R/875F1DCE 2015-07-17 [expires: 2016-07-16]
uid Phil Frost
sub 2048R/A6830C07 2015-07-17 [expires: 2016-07-16]
sub 2048R/25DDB75D 2015-07-17 [expires: 2016-07-16]

pub 4096R/EC8C9492 2014-04-26
uid Keybase.io Merkle Signing (v1)
sub 4096R/8080955B 2014-04-26
sub 4096R/49DA99D5 2014-04-26 [expires: 2024-04-23]

pub 2048R/04D4F4B0 2014-05-07 [expires: 2018-05-07]
uid Kyle Tilman
sub 2048R/A108DCDA 2014-05-07 [expires: 2018-05-07]
```

Note Kian's key is not anywhere in my pubring.gpg. I'm expecting that it will be based on my observation that this works for other keybase users (you can see I have tilman's key), and the "info: Success!" message.

On manually importing his key, I see that it is expired. Is that why?

``` console
$ curl -s https://keybase.io/kian/key.asc | gpg --import
gpg: key 7C8EA90C: public key "Kian Mohageri " imported
gpg: Total number processed: 1
gpg: imported: 1
$ gpg --edit-key kian.mohageri@paperg.com
gpg (GnuPG) 1.4.18; Copyright (C) 2014 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

pub 1024D/7C8EA90C created: 2009-12-22 expired: 2014-12-21 usage: SCA
trust: unknown validity: expired
sub 2048g/50434F73 created: 2009-12-22 expired: 2014-12-21 usage: E
[ expired] (1). Kian Mohageri
```

Reproduce the report with keybase 0.8.12 by tracking kian, then compare the local keyring with the GnuPG output and the manually imported key. Determine how tracking handles an expired public key; done means the behavior is corrected or the reason for the successful message and missing key is clearly documented.

Written by the indexing model from the issue text.