Directly removing floatingip does not remove mac entries from Table 19

1) After floatingip is associated to the VM, directly doing a floating-ip delete.
(neutron floatingip-delete <floatingip-uuid>)

2) The floatingipport will get deleted (observe neutron port-list). But floatingipportmac mac-address should disappear from Table 19.

To fix the removal of mac-address entry from Table-19.