Do not call directly vmops.attach_volume
Do not call directly vmops.attach_volume

Relates to blueprint xenapi-volume-drivers

Driver already have an attach_volume function call which calls
volumeops.attach_volume. This change replaces the direct
volumeops.attach_volume calls with driver.attach_volume, so that
driver.attach_volume will be the entry point for attaching the volume.

Change-Id: I86e7c7df3d37076d7b7945f3504c7f305dce6820

Juniper/nova,rickerc/nova_audit,JioCloud/nova,Metaswitch/calico-nova,tudorvio/nova,Tehsmash/nova,kimjaejoong/nova,TieWei/nova,rajalokan/nova,badock/nova,klmitch/nova,shahar-stratoscale/nova,bgxavier/nova,Stavitsky/nova,mahak/nova,BeyondTheClouds/nova,citrix-openstack-build/nova,barnsnake351/nova,sridevikoushik31/nova,sridevikoushik31/openstack,tudorvio/nova,maoy/zknova,felixma/nova,MountainWei/nova,zaina/nova,nikesh-mahalka/nova,petrutlucian94/nova_dev,leilihh/nova,isyippee/nova,cernops/nova,raildo/nova,redhat-openstack/nova,virtualopensystems/nova,cloudbase/nova,TwinkleChawla/nova,jianghuaw/nova,petrutlucian94/nova,DirectXMan12/nova-hacking,houshengbo/nova_vmware_compute_driver,ewindisch/nova,yosshy/nova,takeshineshiro/nova,vladikr/nova_drafts,Brocade-OpenSource/OpenStack-DNRM-Nova,DirectXMan12/nova-hacking,leilihh/novaha,Juniper/nova,phenoxim/nova,Francis-Liu/animated-broccoli,cloudbau/nova,shail2810/nova,vladikr/nova_drafts,gspilio/nova,JianyuWang/nova,aristanetworks/arista-ovs-nova,NeCTAR-RC/nova,affo/nova,mahak/nova,fnordahl/nova,klmitch/nova,ewindisch/nova,mikalstill/nova,dims/nova,maelnor/nova,aristanetworks/arista-ovs-nova,shootstar/novatest,BeyondTheClouds/nova,TieWei/nova,bigswitch/nova,JioCloud/nova,Yusuke1987/openstack_template,tealover/nova,vmturbo/nova,hanlind/nova,j-carpentier/nova,openstack/nova,zaina/nova,shootstar/novatest,dims/nova,houshengbo/nova_vmware_compute_driver,mgagne/nova,silenceli/nova,Brocade-OpenSource/OpenStack-DNRM-Nova,scripnichenko/nova,eharney/nova,CloudServer/nova,cyx1231st/nova,spring-week-topos/nova-week,belmiromoreira/nova,cloudbase/nova-virtualbox,CiscoSystems/nova,maoy/zknova,Triv90/Nova,rahulunair/nova,yosshy/nova,thomasem/nova,gooddata/openstack-nova,bigswitch/nova,orbitfp7/nova,raildo/nova,devoid/nova,bgxavier/nova,maoy/zknova,silenceli/nova,BeyondTheClouds/nova,barnsnake351/nova,SUSE-Cloud/nova,belmiromoreira/nova,whitepages/nova,yatinkumbhare/openstack-nova,sridevikoushik31/openstack,citrix-openstack-build/nova,rajalokan/nova,scripnichenko/nova,berrange/nova,dstroppa/openstack-smartos-nova-grizzly,plumgrid/plumgrid-nova,orbitfp7/nova,iuliat/nova,sacharya/nova,mmnelemane/nova,luogangyi/bcec-nova,Triv90/Nova,imsplitbit/nova,whitepages/nova,devendermishrajio/nova,cloudbau/nova,blueboxgroup/nova,noironetworks/nova,CiscoSystems/nova,sebrandon1/nova,mgagne/nova,openstack/nova,viggates/nova,mahak/nova,gooddata/openstack-nova,ted-gould/nova,cloudbase/nova,hanlind/nova,viggates/nova,CCI-MOC/nova,varunarya10/nova_test_latest,Yuriy-Leonov/nova,sridevikoushik31/nova,j-carpentier/nova,cernops/nova,plumgrid/plumgrid-nova,devendermishrajio/nova_test_latest,dstroppa/openstack-smartos-nova-grizzly,zhimin711/nova,bclau/nova,JioCloud/nova_test_latest,eonpatapon/nova,joker946/nova,CEG-FYP-OpenStack/scheduler,fajoy/nova,gspilio/nova,qwefi/nova,fajoy/nova,virtualopensystems/nova,Yusuke1987/openstack_template,double12gzh/nova,blueboxgroup/nova,tealover/nova,tanglei528/nova,fajoy/nova,openstack/nova,vmturbo/nova,isyippee/nova,Juniper/nova,edulramirez/nova,apporc/nova,mandeepdhami/nova,cyx1231st/nova,projectcalico/calico-nova,jianghuaw/nova,mikalstill/nova,noironetworks/nova,vmturbo/nova,devoid/nova,LoHChina/nova,OpenAcademy-OpenStack/nova-scheduler,CEG-FYP-OpenStack/scheduler,alexandrucoman/vbox-nova-driver,LoHChina/nova,watonyweng/nova,alvarolopez/nova,tianweizhang/nova,phenoxim/nova,TwinkleChawla/nova,berrange/nova,zzicewind/nova,zzicewind/nova,kimjaejoong/nova,apporc/nova,alaski/nova,aristanetworks/arista-ovs-nova,ntt-sic/nova,ruslanloman/nova,rahulunair/nova,double12gzh/nova,Triv90/Nova,SUSE-Cloud/nova,maheshp/novatest,zhimin711/nova,CloudServer/nova,yrobla/nova,projectcalico/calico-nova,jianghuaw/nova,devendermishrajio/nova,rahulunair/nova,akash1808/nova,shahar-stratoscale/nova,redhat-openstack/nova,MountainWei/nova,eharney/nova,jeffrey4l/nova,Metaswitch/calico-nova,Yuriy-Leonov/nova,Tehsmash/nova,affo/nova,sridevikoushik31/nova,dstroppa/openstack-smartos-nova-grizzly,gspilio/nova,sridevikoushik31/openstack,ntt-sic/nova,adelina-t/nova,leilihh/novaha,qwefi/nova,jeffrey4l/nova,badock/nova,dawnpower/nova,bclau/nova,saleemjaveds/https-github.com-openstack-nova,rickerc/nova_audit,maheshp/novatest,cloudbase/nova-virtualbox,luogangyi/bcec-nova,CCI-MOC/nova,Stavitsky/nova,cloudbase/nova,OpenAcademy-OpenStack/nova-scheduler,edulramirez/nova,watonyweng/nova,petrutlucian94/nova_dev,rrader/nova-docker-plugin,sebrandon1/nova,rajalokan/nova,klmitch/nova,alaski/nova,gooddata/openstack-nova,akash1808/nova_test_latest,klmitch/nova,devendermishrajio/nova_test_latest,felixma/nova,thomasem/nova,tangfeixiong/nova,yrobla/nova,alexandrucoman/vbox-nova-driver,hanlind/nova,eonpatapon/nova,rrader/nova-docker-plugin,NeCTAR-RC/nova,tangfeixiong/nova,vmturbo/nova,joker946/nova,dawnpower/nova,shail2810/nova,sacharya/nova,ted-gould/nova,angdraug/nova,tanglei528/nova,eayunstack/nova,varunarya10/nova_test_latest,rajalokan/nova,iuliat/nova,JianyuWang/nova,eayunstack/nova,sebrandon1/nova,spring-week-topos/nova-wee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