Unimgr:L3 service: arp timeout is not initialized on arp reply

add a tenant with a L3 service:
1CPE - add more than 1 sub interface (IP-UNI) on each port

sent traffic from interface 1 to interface 2 - ok
delete the configuration (tenant,service,int...)
arp entries are removed from:
http://<odl-ip>:8181/restconf/operational/neutronvpn:neutron-vpn-portip-port-data/
however according to Konsta the the arp entries are still cashed so the arp timer continues to run

perform the test again (add tenant with L3 serivce..)
port sends arp req. to learn the mac of the dst ip and receives arp reply
however sending traffic at this point sometimes fails
the port sends again the same arp req. even though it received a reply several sec before

see attached capture
110.1.1.2 - host behind uni1 sub-interface1 (110.1.1.1/29)
110.1.1.10 - host behind uni1 sub-interface2 (110.1.1.9/29)