This is far from correct and will not accept a wide set of valid
email addresses, but it is better than what we used to have and
so far only one person complained about that.

Task-number: QTCREATORBUG-12472
Change-Id: I0d7ed19c9811af0ce28218c40d79988d26cb588b
Reviewed-by: Orgad Shaneh <orgads@gmail.com>