When a subnet is deleted all the SG enables ports needs to rebind with elan id and replace the SG flows to match elan id instead of vpn id.

Steps to reproduce
1)Create two vm with default SG.
2)add the vm network to a router
3)delete the vm network.

Expected Output

SG flows should be rewritten to match vpnid.

Actual Output
SG flows are not rewritten, with elan id. Both flows matching elan and vpnid co-exist.