flow is deleted so flow mgmt info is NULL. so added check for this closes-bug: #1715751
flow is deleted so flow mgmt info is NULL. so added check for this
closes-bug: #1715751

Change-Id: Iff10388b8c0b9edd5642cc45aaab2787c4e014ce

nischalsheth/contrail-controller,eonpatapon/contrail-controller,eonpatapon/contrail-controller,nischalsheth/contrail-controller,rombie/contrail-controller,nischalsheth/contrail-controller,nischalsheth/contrail-controller,eonpatapon/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,nischalsheth/contrail-controller,rombie/contrail-controller,nischalsheth/contrail-controller,eonpatapon/contrail-controller,rombie/contrail-controller,nischalsheth/contrail-controller,nischalsheth/contrail-controller,rombie/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller