Change scenario name in rally-*-fakevirt jobs

We have 3 rally job templates: default, neutron and fakevirt. So
scenario name should be generated according to template:

 {project}.yaml - for default
 {project}-neutron.yaml - for neutron
 {project}-fakevirt.yaml - for nova with fakevirt driver

Change-Id: I2521ddf14b187595e44333cbaf747d1a182cf943