Refactors handling of detach volume
Refactors handling of detach volume

 * removes unnecessary flags in detach_volume call
 * stops double detach reported in bug 887402
 * moves volume.API() into init

Change-Id: I65332cabedf2edb88acb48b3293cba291d440238

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