libvirt: Decomposition plug hybrid methods in vif
libvirt: Decomposition plug hybrid methods in vif

It'll be better if do not use nearly duplicated code
in different locations.

Just separated duplicated code into new method.

Change-Id: I1f941fa36e249f47dec5cc5a48e7e039d27b5377

dawnpower/nova,thomasem/nova,jianghuaw/nova,alaski/nova,cloudbase/nova-virtualbox,alvarolopez/nova,ruslanloman/nova,zhimin711/nova,mmnelemane/nova,rajalokan/nova,gooddata/openstack-nova,mikalstill/nova,eonpatapon/nova,Juniper/nova,NeCTAR-RC/nova,mmnelemane/nova,rahulunair/nova,barnsnake351/nova,cloudbase/nova,alaski/nova,dims/nova,hanlind/nova,joker946/nova,ruslanloman/nova,watonyweng/nova,CEG-FYP-OpenStack/scheduler,openstack/nova,rajalokan/nova,scripnichenko/nova,adelina-t/nova,dims/nova,petrutlucian94/nova,gooddata/openstack-nova,cloudbase/nova,sebrandon1/nova,kimjaejoong/nova,shail2810/nova,Stavitsky/nova,TwinkleChawla/nova,blueboxgroup/nova,mikalstill/nova,akash1808/nova_test_latest,JioCloud/nova,petrutlucian94/nova,BeyondTheClouds/nova,edulramirez/nova,varunarya10/nova_test_latest,bigswitch/nova,klmitch/nova,whitepages/nova,mandeepdhami/nova,j-carpentier/nova,affo/nova,affo/nova,takeshineshiro/nova,raildo/nova,rajalokan/nova,vmturbo/nova,BeyondTheClouds/nova,JioCloud/nova_test_latest,Francis-Liu/animated-broccoli,sebrandon1/nova,cernops/nova,alvarolopez/nova,thomasem/nova,ted-gould/nova,zaina/nova,belmiromoreira/nova,CCI-MOC/nova,phenoxim/nova,klmitch/nova,adelina-t/nova,hanlind/nova,TwinkleChawla/nova,varunarya10/nova_test_latest,MountainWei/nova,orbitfp7/nova,rahulunair/nova,whitepages/nova,akash1808/nova,orbitfp7/nova,isyippee/nova,JianyuWang/nova,phenoxim/nova,sebrandon1/nova,devendermishrajio/nova_test_latest,belmiromoreira/nova,tudorvio/nova,zhimin711/nova,mgagne/nova,yosshy/nova,vmturbo/nova,devendermishrajio/nova,yatinkumbhare/openstack-nova,dawnpower/nova,tangfeixiong/nova,Francis-Liu/animated-broccoli,apporc/nova,Juniper/nova,iuliat/nova,openstack/nova,akash1808/nova,alexandrucoman/vbox-nova-driver,yatinkumbhare/openstack-nova,vmturbo/nova,LoHChina/nova,scripnichenko/nova,CloudServer/nova,mandeepdhami/nova,bgxavier/nova,felixma/nova,fnordahl/nova,takeshineshiro/nova,jianghuaw/nova,tealover/nova,tangfeixiong/nova,cyx1231st/nova,edulramirez/nova,jianghuaw/nova,noironetworks/nova,jeffrey4l/nova,kimjaejoong/nova,MountainWei/nova,blueboxgroup/nova,joker946/nova,isyippee/nova,zzicewind/nova,tudorvio/nova,shail2810/nova,mahak/nova,double12gzh/nova,devendermishrajio/nova,bigswitch/nova,hanlind/nova,klmitch/nova,tealover/nova,cyx1231st/nova,alexandrucoman/vbox-nova-driver,akash1808/nova_test_latest,zaina/nova,CloudServer/nova,ted-gould/nova,Yusuke1987/openstack_template,nikesh-mahalka/nova,double12gzh/nova,CEG-FYP-OpenStack/scheduler,bgxavier/nova,mahak/nova,Juniper/nova,Stavitsky/nova,openstack/nova,cernops/nova,barnsnake351/nova,mahak/nova,JianyuWang/nova,rajalokan/nova,NeCTAR-RC/nova,cernops/nova,fnordahl/nova,mgagne/nova,nikesh-mahalka/nova,Juniper/nova,zzicewind/nova,cloudbase/nova-virtualbox,jeffrey4l/nova,eonpatapon/nova,rahulunair/nova,JioCloud/nova,raildo/nova,j-carpentier/nova,gooddata/openstack-nova,cloudbase/nova,iuliat/nova,Tehsmash/nova,mikalstill/nova,klmitch/nova,JioCloud/nova_test_latest,CCI-MOC/nova,BeyondTheClouds/nova,LoHChina/nova,watonyweng/nova,Tehsmash/nova,felixma/nova,jianghuaw/nova,yosshy/nova,noironetworks/nova,devendermishrajio/nova_test_latest,vmturbo/nova,gooddata/openstack-nova,Yusuke1987/openstack_template,apporc/nova