Remove update lockmode from compute_node_get_by_host
Remove update lockmode from compute_node_get_by_host

Fixes bug #948066

This commit removes the usage of an update cursor so postgres
doesn't raise the error below
SELECT FOR UPDATE/SHARE cannot be applied to the nullable side of
an outer join

Change-Id: Ia1ede22df38d5f6a24372e0ad8ec25151ad195c7

usc-isi/extra-specs,gooddata/openstack-nova,cernops/nova,projectcalico/calico-nova,OpenAcademy-OpenStack/nova-scheduler,edulramirez/nova,mahak/nova,jianghuaw/nova,berrange/nova,Stavitsky/nova,BeyondTheClouds/nova,devendermishrajio/nova,rahulunair/nova,ntt-sic/nova,devendermishrajio/nova_test_latest,mahak/nova,Tehsmash/nova,gooddata/openstack-nova,NoBodyCam/TftpPxeBootBareMetal,devoid/nova,usc-isi/nova,isyippee/nova,virtualopensystems/nova,petrutlucian94/nova_dev,dims/nova,psiwczak/openstack,CiscoSystems/nova,Francis-Liu/animated-broccoli,plumgrid/plumgrid-nova,yrobla/nova,eharney/nova,ruslanloman/nova,sacharya/nova,thomasem/nova,vmturbo/nova,sridevikoushik31/openstack,apporc/nova,cloudbau/nova,sridevikoushik31/openstack,psiwczak/openstack,belmiromoreira/nova,luogangyi/bcec-nova,savi-dev/nova,zaina/nova,vladikr/nova_drafts,devoid/nova,Juniper/nova,JianyuWang/nova,JioCloud/nova,NoBodyCam/TftpPxeBootBareMetal,tealover/nova,petrutlucian94/nova_dev,usc-isi/nova,watonyweng/nova,JioCloud/nova_test_latest,mikalstill/nova,Metaswitch/calico-nova,BeyondTheClouds/nova,projectcalico/calico-nova,DirectXMan12/nova-hacking,double12gzh/nova,whitepages/nova,NewpTone/stacklab-nova,akash1808/nova_test_latest,kimjaejoong/nova,yosshy/nova,cyx1231st/nova,josephsuh/extra-specs,takeshineshiro/nova,whitepages/nova,sebrandon1/nova,paulmathews/nova,sebrandon1/nova,nikesh-mahalka/nova,petrutlucian94/nova,yatinkumbhare/openstack-nova,adelina-t/nova,fnordahl/nova,cloudbase/nova,plumgrid/plumgrid-nova,saleemjaveds/https-github.com-openstack-nova,Yuriy-Leonov/nova,SUSE-Cloud/nova,maheshp/novatest,openstack/nova,aristanetworks/arista-ovs-nova,rahulunair/nova,eharney/nova,CloudServer/nova,ewindisch/nova,spring-week-topos/nova-week,imsplitbit/nova,orbitfp7/nova,TwinkleChawla/nova,sileht/deb-openstack-nova,bigswitch/nova,usc-isi/extra-specs,blueboxgroup/nova,CEG-FYP-OpenStack/scheduler,gspilio/nova,orbitfp7/nova,sacharya/nova,OpenAcademy-OpenStack/nova-scheduler,eonpatapon/nova,CiscoSystems/nova,fajoy/nova,sebrandon1/nova,affo/nova,devendermishrajio/nova,viggates/nova,dstroppa/openstack-smartos-nova-grizzly,alvarolopez/nova,adelina-t/nova,rrader/nova-docker-plugin,houshengbo/nova_vmware_compute_driver,alexandrucoman/vbox-nova-driver,badock/nova,eneabio/nova,Metaswitch/calico-nova,savi-dev/nova,tangfeixiong/nova,felixma/nova,ted-gould/nova,bclau/nova,Juniper/nova,angdraug/nova,houshengbo/nova_vmware_compute_driver,josephsuh/extra-specs,mikalstill/nova,JioCloud/nova,klmitch/nova,cloudbase/nova-virtualbox,belmiromoreira/nova,Triv90/Nova,NeCTAR-RC/nova,dims/nova,qwefi/nova,leilihh/nova,sileht/deb-openstack-nova,gspilio/nova,yosshy/nova,redhat-openstack/nova,Juniper/nova,gooddata/openstack-nova,cloudbase/nova,noironetworks/nova,rickerc/nova_audit,TieWei/nova,rajalokan/nova,shootstar/novatest,Francis-Liu/animated-broccoli,DirectXMan12/nova-hacking,maoy/zknova,joker946/nova,rajalokan/nova,openstack/nova,CloudServer/nova,leilihh/nova,usc-isi/nova,JianyuWang/nova,houshengbo/nova_vmware_compute_driver,virtualopensystems/nova,zhimin711/nova,DirectXMan12/nova-hacking,tianweizhang/nova,Tehsmash/nova,ntt-sic/nova,dawnpower/nova,hanlind/nova,jianghuaw/nova,iuliat/nova,leilihh/novaha,j-carpentier/nova,sridevikoushik31/nova,paulmathews/nova,rrader/nova-docker-plugin,iuliat/nova,yatinkumbhare/openstack-nova,yrobla/nova,devendermishrajio/nova_test_latest,takeshineshiro/nova,double12gzh/nova,fnordahl/nova,alaski/nova,affo/nova,maheshp/novatest,shail2810/nova,shootstar/novatest,scripnichenko/nova,alaski/nova,TieWei/nova,tudorvio/nova,NoBodyCam/TftpPxeBootBareMetal,openstack/nova,TwinkleChawla/nova,jeffrey4l/nova,MountainWei/nova,kimjaejoong/nova,aristanetworks/arista-ovs-nova,phenoxim/nova,maoy/zknova,josephsuh/extra-specs,fajoy/nova,hanlind/nova,jeffrey4l/nova,maoy/zknova,CCI-MOC/nova,CEG-FYP-OpenStack/scheduler,fajoy/nova,zaina/nova,varunarya10/nova_test_latest,sridevikoushik31/nova,BeyondTheClouds/nova,scripnichenko/nova,felixma/nova,alexandrucoman/vbox-nova-driver,dstroppa/openstack-smartos-nova-grizzly,mahak/nova,akash1808/nova_test_latest,vmturbo/nova,rajalokan/nova,saleemjaveds/https-github.com-openstack-nova,bigswitch/nova,rahulunair/nova,MountainWei/nova,tealover/nova,isyippee/nova,mikalstill/nova,hanlind/nova,sridevikoushik31/openstack,alvarolopez/nova,cernops/nova,tudorvio/nova,klmitch/nova,klmitch/nova,maelnor/nova,akash1808/nova,SUSE-Cloud/nova,eneabio/nova,silenceli/nova,mgagne/nova,rajalokan/nova,eayunstack/nova,tangfeixiong/nova,psiwczak/openstack,Yuriy-Leonov/nova,Brocade-OpenSource/OpenStack-DNRM-Nova,barnsnake351/nova,shail2810/nova,j-carpentier/nova,dstroppa/openstack-smartos-nova-grizzly,shahar-stratoscale/nova,petrutlucian94/nova,apporc/nova,zhimin711/nova,maheshp/novatest,akash1808/nova,thomasem/nova,tanglei528/nova,badock/nova,blueboxgroup/nova,jianghuaw/nova,gspilio/nova,edulramirez/nova,Stavitsky/nova,qwefi/nova,silenceli/nova,NewpTone/stacklab-nova,sridevikoushik31/nova,dawnpower/nova,ewindisch/nova,gooddata/openstack-nova,spring-week-to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