Add ports information to the dict returned by create_router and
update_router

DHC-1175

The rug needs those information to be sure the created router
has ports on the mgt and the external networks

Change-Id: Ic068b088595878dc41cc5fece49611b37c6e044e
Signed-off-by: Rosario Di Somma <rosario.disomma@dreamhost.com>