Allow Javelin to create volumes without servers
Allow Javelin to create volumes without servers

This patch will modify Javelin so that it only attempts to attach a
volume if servers are defined.

Change-Id: I9e0c0ca59774051a3c65ee3118b470e5133cace4

masayukig/tempest,tonyli71/tempest,NexusIS/tempest,neerja28/Tempest,nunogt/tempest,neerja28/Tempest,zsoltdudas/lis-tempest,manasi24/jiocloud-tempest-qatempest,sebrandon1/tempest,openstack/tempest,dkalashnik/tempest,izadorozhna/tempest,LIS/lis-tempest,rakeshmi/tempest,masayukig/tempest,pandeyop/tempest,varunarya10/tempest,eggmaster/tempest,akash1808/tempest,Juraci/tempest,hpcloud-mon/tempest,flyingfish007/tempest,nunogt/tempest,bigswitch/tempest,sebrandon1/tempest,izadorozhna/tempest,redhat-cip/tempest,pczerkas/tempest,varunarya10/tempest,xbezdick/tempest,cisco-openstack/tempest,openstack/tempest,Juniper/tempest,Juniper/tempest,afaheem88/tempest,zsoltdudas/lis-tempest,manasi24/jiocloud-tempest-qatempest,yamt/tempest,alinbalutoiu/tempest,yamt/tempest,hpcloud-mon/tempest,JioCloud/tempest,cisco-openstack/tempest,Tesora/tesora-tempest,manasi24/tempest,bigswitch/tempest,alinbalutoiu/tempest,redhat-cip/tempest,JioCloud/tempest,jaspreetw/tempest,tonyli71/tempest,FujitsuEnablingSoftwareTechnologyGmbH/tempest,vedujoshi/tempest,NexusIS/tempest,flyingfish007/tempest,danielmellado/tempest,Tesora/tesora-tempest,roopali8/tempest,tudorvio/tempest,vedujoshi/tempest,danielmellado/tempest,hayderimran7/tempest,dkalashnik/tempest,afaheem88/tempest,eggmaster/tempest,manasi24/tempest,pczerkas/tempest,LIS/lis-tempest,pandeyop/tempest,akash1808/tempest,jaspreetw/tempest,FujitsuEnablingSoftwareTechnologyGmbH/tempest,Juraci/tempest,hayderimran7/tempest,tudorvio/tempest,xbezdick/tempest,roopali8/tempest,rakeshmi/tempest