ERROR No sigchain was available

When attempting to follow or track someone, I keep getting the error "ERROR No sigchain was available" - which isn't very helpful. It's totally unclear if I'm doing something wrong (I don't think so - keybase track foo_user) or if something is wrong in keybase. I'm positive foo_user exists, and a search results in plenty of identity information.

Start by reproducing the `keybase track foo_user` command with an account that appears in search results, then inspect how the client handles the missing sigchain. Determine whether the problem is with tracking or the user's sigchain, and make the resulting error identify the cause clearly; verify the command either tracks successfully or reports a useful diagnostic.

Written by the indexing model from the issue text.