DB: use assertIsNotNone for unit test
DB: use assertIsNotNone for unit test

Commit 48de2895b9a550a0944b31212349275605a4061d added a
validation that should have used assertIsNotNone.

TrivialFix

Change-Id: Ib6b82d90bb163f7ee06c916e52d3dd40ff2ba34d

apporc/nova,saleemjaveds/https-github.com-openstack-nova,viggates/nova,badock/nova,jeffrey4l/nova,projectcalico/calico-nova,sebrandon1/nova,Tehsmash/nova,Yusuke1987/openstack_template,mgagne/nova,bigswitch/nova,klmitch/nova,barnsnake351/nova,cyx1231st/nova,NeCTAR-RC/nova,double12gzh/nova,TwinkleChawla/nova,tudorvio/nova,zzicewind/nova,watonyweng/nova,Juniper/nova,tudorvio/nova,Francis-Liu/animated-broccoli,ted-gould/nova,TwinkleChawla/nova,affo/nova,kimjaejoong/nova,jianghuaw/nova,tangfeixiong/nova,hanlind/nova,badock/nova,virtualopensystems/nova,joker946/nova,tianweizhang/nova,Juniper/nova,jianghuaw/nova,mahak/nova,redhat-openstack/nova,gooddata/openstack-nova,CEG-FYP-OpenStack/scheduler,rahulunair/nova,bgxavier/nova,akash1808/nova,dims/nova,thomasem/nova,klmitch/nova,j-carpentier/nova,affo/nova,varunarya10/nova_test_latest,mahak/nova,ruslanloman/nova,NeCTAR-RC/nova,devendermishrajio/nova_test_latest,saleemjaveds/https-github.com-openstack-nova,belmiromoreira/nova,felixma/nova,cernops/nova,virtualopensystems/nova,mikalstill/nova,alvarolopez/nova,iuliat/nova,MountainWei/nova,CloudServer/nova,jianghuaw/nova,Francis-Liu/animated-broccoli,openstack/nova,rajalokan/nova,rajalokan/nova,vmturbo/nova,Stavitsky/nova,raildo/nova,vmturbo/nova,takeshineshiro/nova,mikalstill/nova,vladikr/nova_drafts,JioCloud/nova_test_latest,nikesh-mahalka/nova,blueboxgroup/nova,sebrandon1/nova,noironetworks/nova,noironetworks/nova,Juniper/nova,hanlind/nova,scripnichenko/nova,jeffrey4l/nova,klmitch/nova,petrutlucian94/nova,felixma/nova,isyippee/nova,tealover/nova,mmnelemane/nova,redhat-openstack/nova,rahulunair/nova,joker946/nova,openstack/nova,bigswitch/nova,Metaswitch/calico-nova,LoHChina/nova,j-carpentier/nova,yatinkumbhare/openstack-nova,openstack/nova,CCI-MOC/nova,yatinkumbhare/openstack-nova,zzicewind/nova,zaina/nova,mikalstill/nova,cernops/nova,berrange/nova,bgxavier/nova,MountainWei/nova,zhimin711/nova,cloudbase/nova-virtualbox,maelnor/nova,fnordahl/nova,cloudbase/nova-virtualbox,iuliat/nova,cloudbase/nova,ruslanloman/nova,mandeepdhami/nova,devendermishrajio/nova,Tehsmash/nova,alexandrucoman/vbox-nova-driver,belmiromoreira/nova,silenceli/nova,shail2810/nova,angdraug/nova,raildo/nova,akash1808/nova_test_latest,varunarya10/nova_test_latest,cloudbase/nova,isyippee/nova,jianghuaw/nova,whitepages/nova,eayunstack/nova,BeyondTheClouds/nova,gooddata/openstack-nova,Stavitsky/nova,hanlind/nova,rajalokan/nova,takeshineshiro/nova,yosshy/nova,tealover/nova,devendermishrajio/nova,yosshy/nova,sebrandon1/nova,dawnpower/nova,petrutlucian94/nova,dawnpower/nova,akash1808/nova,JioCloud/nova,vmturbo/nova,barnsnake351/nova,tianweizhang/nova,CEG-FYP-OpenStack/scheduler,JianyuWang/nova,dims/nova,double12gzh/nova,klmitch/nova,fnordahl/nova,orbitfp7/nova,LoHChina/nova,rajalokan/nova,whitepages/nova,eonpatapon/nova,watonyweng/nova,kimjaejoong/nova,eayunstack/nova,JianyuWang/nova,apporc/nova,BeyondTheClouds/nova,akash1808/nova_test_latest,zhimin711/nova,alvarolopez/nova,CloudServer/nova,edulramirez/nova,BeyondTheClouds/nova,edulramirez/nova,zaina/nova,Juniper/nova,orbitfp7/nova,alaski/nova,phenoxim/nova,Yusuke1987/openstack_template,viggates/nova,mahak/nova,JioCloud/nova_test_latest,adelina-t/nova,mandeepdhami/nova,vmturbo/nova,berrange/nova,shail2810/nova,alaski/nova,maelnor/nova,cernops/nova,projectcalico/calico-nova,blueboxgroup/nova,rahulunair/nova,mgagne/nova,angdraug/nova,vladikr/nova_drafts,tangfeixiong/nova,mmnelemane/nova,cloudbase/nova,ted-gould/nova,silenceli/nova,devendermishrajio/nova_test_latest,Metaswitch/calico-nova,gooddata/openstack-nova,cyx1231st/nova,thomasem/nova,JioCloud/nova,nikesh-mahalka/nova,adelina-t/nova,scripnichenko/nova,phenoxim/nova,eonpatapon/nova,CCI-MOC/nova,gooddata/openstack-nova,alexandrucoman/vbox-nova-driver