libvirt: unused imported option default_ephemeral_format
libvirt: unused imported option default_ephemeral_format

An unused imported conf "default_ephemeral_format" needs to
be remove from the driver.

Change-Id: I072c63eaf94e457190b382df7e166706b065f525

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