BUG-1953: fix SAL compatility layer

Sal compatibility produces pure addresses instead of prefixes as
dictated by the model. Fix moth tests and implementation to emit
prefixes.

Change-Id: I1aca04c0fc22aa973d9578fea33550194c6f9264
Signed-off-by: Robert Varga <rovarga@cisco.com>
(cherry picked from commit da19620fa7bf6af3ab28c90ebd4df8eec920ec2c)