IPV6 address should be removed automatically when router interface deleted

Description:

IPV6 address should be removed automatically when router interface deleted

Steps:

1. Create network,subnet(iPv4) and port and boot VM.(check ipv4 address discovered)
2. Create subnet with SLAAC(Ipv6) mode and add subnet to router and boot VM,verify all VM discovered both IPv4 and IPV6 address.

3. Removed subnet(IPV6) from router and check IPV6 address removed in VM where VM associatd to IPV4 subnet.

Result:

Step 3 fails. IPV6 address not removed automatically in VM.