Fix race condition in delete_port method. Fix update_port method
Fix race condition in delete_port method. Fix update_port method

Port can be gone between
  l3plugin.prevent_l3_port_deletion(context, id)
and port query. Need to handle it properly.
ALso need to handle non-existing port in update_port properly.

Closes-Bug: #1266537

Change-Id: Ic203f21db277f83c604a8757a8c421b3fb9ae709

miyakz1192/neutron,mahak/neutron,antonioUnina/neutron,asgard-lab/neutron,shahbazn/neutron,blueboxgroup/neutron,takeshineshiro/neutron,gkotton/neutron,mandeepdhami/neutron,yanheven/neutron,shahbazn/neutron,Juniper/contrail-dev-neutron,suneeth51/neutron,barnsnake351/neutron,alexandrucoman/vbox-neutron-agent,sajuptpm/neutron-ipam,vveerava/Openstack,wenhuizhang/neutron,jumpojoy/neutron,gopal1cloud/neutron,magic0704/neutron,virtualopensystems/neutron,rdo-management/neutron,eonpatapon/neutron,mmnelemane/neutron,huntxu/neutron,silenci/neutron,skyddv/neutron,sebrandon1/neutron,Juniper/contrail-dev-neutron,cernops/neutron,vijayendrabvs/ssl-neutron,dims/neutron,gopal1cloud/neutron,vbannai/neutron,swdream/neutron,aristanetworks/neutron,pnavarro/neutron,CiscoSystems/neutron,vveerava/Openstack,wolverineav/neutron,yuewko/neutron,vijayendrabvs/hap,eonpatapon/neutron,JianyuWang/neutron,NeCTAR-RC/neutron,virtualopensystems/neutron,NeCTAR-RC/neutron,adelina-t/neutron,vijayendrabvs/hap,JioCloud/neutron,sajuptpm/neutron-ipam,antonioUnina/neutron,beagles/neutron_hacking,chitr/neutron,huntxu/neutron,glove747/liberty-neutron,alexandrucoman/vbox-neutron-agent,virtualopensystems/neutron,cernops/neutron,leeseulstack/openstack,cloudbase/neutron,MaximNevrov/neutron,javaos74/neutron,jumpojoy/neutron,yamahata/neutron,watonyweng/neutron,dhanunjaya/neutron,Juniper/neutron,vbannai/neutron,yamahata/neutron,cisco-openstack/neutron,watonyweng/neutron,chitr/neutron,klmitch/neutron,SamYaple/neutron,yuewko/neutron,beagles/neutron_hacking,magic0704/neutron,paninetworks/neutron,Juniper/neutron,aristanetworks/neutron,openstack/neutron,leeseuljeong/leeseulstack_neutron,jerryz1982/neutron,sebrandon1/neutron,leeseulstack/openstack,gkotton/neutron,rdo-management/neutron,Stavitsky/neutron,swdream/neutron,sajuptpm/neutron-ipam,wolverineav/neutron,blueboxgroup/neutron,mmnelemane/neutron,miyakz1192/neutron,mattt416/neutron,bgxavier/neutron,vijayendrabvs/ssl-neutron,CiscoSystems/neutron,paninetworks/neutron,eayunstack/neutron,Stavitsky/neutron,noironetworks/neutron,cisco-openstack/neutron,zhhf/charging,apporc/neutron,vbannai/neutron,leeseuljeong/leeseulstack_neutron,yamahata/tacker,infobloxopen/neutron,javaos74/neutron,blueboxgroup/neutron,bigswitch/neutron,CiscoSystems/neutron,mattt416/neutron,beagles/neutron_hacking,JianyuWang/neutron,noironetworks/neutron,redhat-openstack/neutron,Juniper/contrail-dev-neutron,Juniper/neutron,projectcalico/calico-neutron,glove747/liberty-neutron,vijayendrabvs/hap,Metaswitch/calico-neutron,igor-toga/local-snat,SamYaple/neutron,silenci/neutron,cloudbase/neutron-virtualbox,infobloxopen/neutron,JioCloud/neutron,sasukeh/neutron,redhat-openstack/neutron,igor-toga/local-snat,MaximNevrov/neutron,asgard-lab/neutron,mahak/neutron,yamahata/tacker,vivekanand1101/neutron,vijayendrabvs/ssl-neutron,waltBB/neutron_read,openstack/neutron,openstack/neutron,yanheven/neutron,vivekanand1101/neutron,cloudbase/neutron-virtualbox,suneeth51/neutron,yamahata/neutron,mahak/neutron,adelina-t/neutron,eayunstack/neutron,sasukeh/neutron,dims/neutron,bgxavier/neutron,waltBB/neutron_read,mandeepdhami/neutron,pnavarro/neutron,neoareslinux/neutron,skyddv/neutron,gkotton/neutron,dhanunjaya/neutron,zhhf/charging,Metaswitch/calico-neutron,SmartInfrastructures/neutron,wenhuizhang/neutron,jacknjzhou/neutron,klmitch/neutron,bigswitch/neutron,zhhf/charging,takeshineshiro/neutron,cloudbase/neutron,jacknjzhou/neutron,projectcalico/calico-neutron,yamahata/tacker,apporc/neutron,neoareslinux/neutron,leeseulstack/openstack,barnsnake351/neutron,SmartInfrastructures/neutron,jerryz1982/neutron,leeseuljeong/leeseulstack_neutron,vveerava/Openstack