"Edit" user brings selected "role" accoding to database.

Also update the code that used 'access_type' to be
'role_id'. Delete column 'access_type' since 'role_id' is
what we really need to establish a relationship between
users and their roles.
Validate (js) user role select box.

Just add the select box validation part to
the existing validation function.
Merge branch 'validade_new_edit_user_javascript'.