contacts(fix): avoid saving a contact item before lookup returns

- prevents the contact item from being saved to disk before the
  ns-lookup returns a valid ringid

- adds ringid directly to contact item if a ringid is searched,
  prior to the ns-lookup returning

Change-Id: I8bf6cce2c2181a5552affd5adb0b621d2b926bdb
Reviewed-by: Nicolas Jäger <nicolas.jager@savoirfairelinux.com>