Check if cinder is enabled before doing anything lvm2 related
Check if cinder is enabled before doing anything lvm2 related

On some system Cinder is not enabled so we can't assume LVM is installed. So
do not try to `sed` /etc/lvm/lvm.conf or clean LVM VG if cinder is not enabled

Change-Id: I09b1a7bee0785e5e1bb7dc96158a654bd3f15c83
Mahito/devstack,group-policy/devstack,dirkmueller/devstack,flavio-fernandes/devstack,ozamiatin/devstack,dtroyer/devstack,group-policy/devstack,vishnugonela/devstack,vishnugonela/devstack,nawawi/openstack,HPCHub/devstack,CloudServer/devstack,wenhuizhang/devstack,pombredanne/devstack,bswartz/devstack,atulpatil301/devstack,wenhuizhang/devstack,eharney/devstack,richliu/devstack,bq-xiao/devstack,olivierlemasle/devstack,noironetworks/devstack,parul24/devstack,bigswitch/devstack,pczerkas/devstack,herrsechs/devstack,eharney/devstack,noironetworks/devstack,costingalan/devstack,pombredanne/devstack,HPCHub/devstack,costingalan/devstack,pacinete/devstack,mc2014/devstack,mmasaki/devstack,mc2014/devstack,NaokiMiyata/devstack,prithivm/branch01,TwinkleChawla/devstack,openstack-dev/devstack,ozamiatin/devstack,avvocatodemarchis/devstack,nawawi/openstack,avvocatodemarchis/devstack,upadhyay-prashant/devstack,mssumanth/devstack,Mahito/devstack,LoHChina/devstack,j4/devstack,thomasem/devstack,mssumanth/devstack,openstack-dev/devstack,pacinete/devstack,olivierlemasle/devstack,dtroyer/devstack,LoHChina/devstack,varunarya10/devstack,CloudServer/devstack,j4/devstack,liuquansheng47/devstack,liuquansheng47/devstack,parul24/devstack,TwinkleChawla/devstack,flavio-fernandes/devstack,richliu/devstack,upadhyay-prashant/devstack,herrsechs/devstack,vsham20/devstack,thomasem/devstack,dirkmueller/devstack,vsham20/devstack,NaokiMiyata/devstack,mmasaki/devstack,varunarya10/devstack,samgoon/devstack,samgoon/devstack,bq-xiao/devstack,pczerkas/devstack,prithivm/branch01,bswartz/devstack,bigswitch/devstack,atulpatil301/devstack