Login error messages not getting fully propagated to the UI

[shana]

When a user hasn't verified their email, octokit returns

{"message":"Validation Failed","errors":[{"resource":"OauthAccess","code":"custom","field":"user","message":"user must have a verified email address in order to authenticate via OAuth"}],"documentation_url":"https://developer.github.com/v3/oauth_authorizations/#get-or-create-an-authorization-for-a-specific-app"}    at Octokit.Connection.HandleErrors(IResponse response) in Y:\jenkins\workspace\GitHub for Visual Studio speakeasy jenkinskeep\submodules\octokit.net\Octokit\Http\Connection.cs:line 563

but our login UI just says "Could not connect to github.com". We need to propagate these messages properly so users don't get confused about why things are failing.

[grokys]

👍 Yes, this bit me just the other day.

[grokys]

Fixed by #352