Login error improvement

[tleekkul]

Problems

• User already has an account with Hotnow using username-password
• User is trying to log in with another login type (Facebook or Google+)
• Now Odin returns 500 internal server error so the user can't know what's wrong with his login.

Solutions

• Return a better error message like "Invalid login type"

[KayEss]

Why doesn't this automatically link the accounts? Or is this because the email address that comes back from FB or G+ is the same as one that is already in the system?

We need to be careful here if the email address we have against another a/c hasn't been activated yet