Remove family from InterfaceRouteTable object, the family will be indirectly
derived, this keeps it consistent with other VNC Cfg objects, eg: subnets

Bug #1391988

Change-Id: Ibb82e62064a41145b82e28d5686ea6cdf659d148
Merge "Remove family from InterfaceRouteTable object, the family will be indirectly derived, this keeps it consistent with other VNC Cfg objects, eg: subnets" into R2.0