lvm: check if the volume group is present before creating
lvm: check if the volume group is present before creating

There's a bug somewhere in Ansible that causes the volume to be created
twice (or rather created once and then fail every other time)
specifically on GCE.

huodon/microservices-infrastructure,sehqlr/mantl,KaGeN101/mantl,ContainerSolutions/microservices-infrastructure,phnmnl/mantl,abn/microservices-infrastructure,CiscoCloud/mantl,mantl/mantl,phnmnl/mantl,sehqlr/mantl,mantl/mantl,bitium/mantl,huodon/microservices-infrastructure,huodon/microservices-infrastructure,datascienceinc/mantl,CiscoCloud/mantl,huodon/microservices-infrastructure,abn/microservices-infrastructure,ContainerSolutions/microservices-infrastructure,datascienceinc/mantl,huodon/microservices-infrastructure,bitium/mantl,KaGeN101/mantl,CiscoCloud/microservices-infrastructure,CiscoCloud/microservices-infrastructure,abn/microservices-infrastructure