Add missing exception to cell_update()
Add missing exception to cell_update()

Add missing CellNotFound exception to
cell_update() in db.sqlalchemy.api,
which expected from this method.

Change-Id: I25699a08b581922b13ae62708486bdee6f8b0ac6

yosshy/nova,CCI-MOC/nova,ntt-sic/nova,shail2810/nova,orbitfp7/nova,sacharya/nova,cloudbase/nova-virtualbox,JioCloud/nova_test_latest,saleemjaveds/https-github.com-openstack-nova,dawnpower/nova,j-carpentier/nova,gooddata/openstack-nova,cernops/nova,vladikr/nova_drafts,takeshineshiro/nova,cyx1231st/nova,eonpatapon/nova,zzicewind/nova,takeshineshiro/nova,affo/nova,berrange/nova,hanlind/nova,devendermishrajio/nova,virtualopensystems/nova,petrutlucian94/nova,citrix-openstack-build/nova,alexandrucoman/vbox-nova-driver,double12gzh/nova,CiscoSystems/nova,mgagne/nova,sebrandon1/nova,barnsnake351/nova,iuliat/nova,tanglei528/nova,rickerc/nova_audit,gooddata/openstack-nova,ewindisch/nova,qwefi/nova,klmitch/nova,eharney/nova,jeffrey4l/nova,mmnelemane/nova,bclau/nova,sebrandon1/nova,projectcalico/calico-nova,luogangyi/bcec-nova,TieWei/nova,Metaswitch/calico-nova,mmnelemane/nova,cloudbase/nova,maelnor/nova,rahulunair/nova,affo/nova,bigswitch/nova,whitepages/nova,Francis-Liu/animated-broccoli,hanlind/nova,eayunstack/nova,klmitch/nova,devoid/nova,jianghuaw/nova,CCI-MOC/nova,Stavitsky/nova,isyippee/nova,rrader/nova-docker-plugin,edulramirez/nova,isyippee/nova,mgagne/nova,eayunstack/nova,akash1808/nova,rajalokan/nova,tealover/nova,CiscoSystems/nova,thomasem/nova,JioCloud/nova,mahak/nova,citrix-openstack-build/nova,adelina-t/nova,felixma/nova,gooddata/openstack-nova,NeCTAR-RC/nova,shootstar/novatest,varunarya10/nova_test_latest,dims/nova,jianghuaw/nova,scripnichenko/nova,mandeepdhami/nova,cloudbase/nova,leilihh/nova,watonyweng/nova,sebrandon1/nova,rajalokan/nova,vmturbo/nova,rickerc/nova_audit,petrutlucian94/nova_dev,Juniper/nova,viggates/nova,dawnpower/nova,leilihh/novaha,mikalstill/nova,bclau/nova,vmturbo/nova,blueboxgroup/nova,noironetworks/nova,BeyondTheClouds/nova,cloudbau/nova,devendermishrajio/nova,badock/nova,nikesh-mahalka/nova,leilihh/nova,vladikr/nova_drafts,akash1808/nova,ted-gould/nova,petrutlucian94/nova_dev,TwinkleChawla/nova,thomasem/nova,Juniper/nova,bgxavier/nova,barnsnake351/nova,shahar-stratoscale/nova,BeyondTheClouds/nova,CloudServer/nova,fnordahl/nova,tudorvio/nova,noironetworks/nova,belmiromoreira/nova,devendermishrajio/nova_test_latest,silenceli/nova,Yuriy-Leonov/nova,JianyuWang/nova,plumgrid/plumgrid-nova,alexandrucoman/vbox-nova-driver,klmitch/nova,zhimin711/nova,NeCTAR-RC/nova,yatinkumbhare/openstack-nova,mahak/nova,akash1808/nova_test_latest,tangfeixiong/nova,Brocade-OpenSource/OpenStack-DNRM-Nova,devendermishrajio/nova_test_latest,phenoxim/nova,ted-gould/nova,eharney/nova,rahulunair/nova,Yusuke1987/openstack_template,edulramirez/nova,yatinkumbhare/openstack-nova,vmturbo/nova,JianyuWang/nova,rrader/nova-docker-plugin,felixma/nova,apporc/nova,openstack/nova,cloudbase/nova-virtualbox,joker946/nova,CEG-FYP-OpenStack/scheduler,JioCloud/nova,JioCloud/nova_test_latest,tudorvio/nova,j-carpentier/nova,Juniper/nova,imsplitbit/nova,Francis-Liu/animated-broccoli,shail2810/nova,alvarolopez/nova,cyx1231st/nova,Metaswitch/calico-nova,phenoxim/nova,dims/nova,orbitfp7/nova,zhimin711/nova,spring-week-topos/nova-week,gooddata/openstack-nova,akash1808/nova_test_latest,MountainWei/nova,bigswitch/nova,SUSE-Cloud/nova,tianweizhang/nova,alaski/nova,rahulunair/nova,hanlind/nova,openstack/nova,CloudServer/nova,MountainWei/nova,scripnichenko/nova,petrutlucian94/nova,belmiromoreira/nova,devoid/nova,LoHChina/nova,zaina/nova,projectcalico/calico-nova,openstack/nova,varunarya10/nova_test_latest,cloudbau/nova,rajalokan/nova,kimjaejoong/nova,OpenAcademy-OpenStack/nova-scheduler,OpenAcademy-OpenStack/nova-scheduler,CEG-FYP-OpenStack/scheduler,zaina/nova,Tehsmash/nova,klmitch/nova,mikalstill/nova,tealover/nova,ewindisch/nova,zzicewind/nova,tianweizhang/nova,sacharya/nova,watonyweng/nova,double12gzh/nova,DirectXMan12/nova-hacking,plumgrid/plumgrid-nova,leilihh/novaha,DirectXMan12/nova-hacking,badock/nova,Yusuke1987/openstack_template,virtualopensystems/nova,luogangyi/bcec-nova,TwinkleChawla/nova,ruslanloman/nova,blueboxgroup/nova,joker946/nova,redhat-openstack/nova,BeyondTheClouds/nova,berrange/nova,raildo/nova,DirectXMan12/nova-hacking,Yuriy-Leonov/nova,whitepages/nova,adelina-t/nova,Tehsmash/nova,cernops/nova,jianghuaw/nova,rajalokan/nova,shahar-stratoscale/nova,mandeepdhami/nova,Brocade-OpenSource/OpenStack-DNRM-Nova,shootstar/novatest,bgxavier/nova,alvarolopez/nova,tangfeixiong/nova,imsplitbit/nova,raildo/nova,vmturbo/nova,angdraug/nova,saleemjaveds/https-github.com-openstack-nova,ruslanloman/nova,spring-week-topos/nova-week,yosshy/nova,Stavitsky/nova,angdraug/nova,mikalstill/nova,kimjaejoong/nova,eonpatapon/nova,Juniper/nova,redhat-openstack/nova,cloudbase/nova,LoHChina/nova,qwefi/nova,fnordahl/nova,cernops/nova,jeffrey4l/nova,maelnor/nova,SUSE-Cloud/nova,silenceli/nova,nikesh-mahalka/nova,TieWei/nova,viggates/nova,iuliat/nova,mahak/nova,apporc/nova,ntt-sic/nova,tanglei528/nova,jianghuaw/nova,alaski/nova