Added data-locality feature description
Added data-locality feature description

Implements: blueprint rack-and-vms-location-should-pass-to-cluster
Change-Id: I9441bb0af02fd07e3179c817a2d2410c82ab27c7

matips/iosr-2015,bigfootproject/sahara,tellesnobrega/storm_plugin,xme1226/sahara,bigfootproject/sahara,zhujzhuo/Sahara,openstack/sahara,crobby/sahara,esikachev/scenario,zhangjunli177/sahara,henaras/sahara,tellesnobrega/storm_plugin,crobby/sahara,keedio/sahara,zhangjunli177/sahara,egafford/sahara,xme1226/sahara,matips/iosr-2015,tellesnobrega/storm_plugin,henaras/sahara,zhujzhuo/Sahara,zhangjunli177/sahara,citrix-openstack-build/sahara,henaras/sahara,mapr/sahara,zhujzhuo/Sahara,redhat-openstack/sahara,xme1226/sahara,citrix-openstack-build/sahara,redhat-openstack/sahara,ekasitk/sahara,matips/iosr-2015,keedio/sahara,esikachev/sahara-backup,keedio/sahara,ekasitk/sahara,crobby/sahara,redhat-openstack/sahara,esikachev/scenario,mapr/sahara,egafford/sahara,bigfootproject/sahara,esikachev/sahara-backup,esikachev/scenario,openstack/sahara,esikachev/sahara-backup,citrix-openstack-build/sahara,tellesnobrega/sahara,tellesnobrega/sahara,mapr/sahara,ekasitk/sahara