Remove spaces from generated login when user register account
Issue reported by Logan Le Bihan on the mailing list.
When the user has a 2-part last name with space (i.e. Le Bihan), the ID given to the user has a space (i.e. lle bihan). Therefore, the UID is stored with a space (I don’t think that's good), and when the user tries to connect, a “Bad username” pop up due to the space.