Retry on deadlock in instance_metadata_delete
Retry on deadlock in instance_metadata_delete

Add the retry_on_deadlock decorator to the instance_metadata_delete
function in the sqlalchemy db API.  A tempest test failure shows that it
would benefit from it.

Change-Id: I39547fbbbabc310b78493df0dc055bc320995770
Closes-bug: #1226076

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