Bug 1341335: If service chain has been destroyed, delete the corresponding vrf assign rule. If all service chains have been destroyed for an interface, delete the whole table

Change-Id: I48cf2e3c256ebfefa2c264c96d83dc60a6d075d1
Merge "Bug 1341335: If service chain has been destroyed, delete the corresponding vrf assign rule. If all service chains have been destroyed for an interface, delete the whole table"