Misleading error message when adding email already associated to account

[Loïc Gomez]

We got a report from one of our users complaining they can't add an email to their SSO account with this error:
  An Ubuntu One account already exists with this email.

Actually, said email was already associated with their account.

Even though the list of associated emails is printed on screen on the add form, I guess the error should probably be something like:
  Your Ubuntu One account is already associated to this email.

Thank you,
Loïc