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

modules/openstack_project/files/jenkins_job_builder/config/rally.yaml

@@ -112,7 +112,7 @@
 
     builders:
       - devstack-rally-gate:
-          scenario: '{name}-neutron'
+          scenario: '{name}-fakevirt'
           neutron: '0'
           large_ops: '10'