Remove EC2 from Nova gate job

EC2 API was officially removed from Nova.
So we should create separated job for ec2-api project which implements
that API now

Change-Id: I4a7943fe5a6b29a3a22d880d1beb1ae9ca7e797d

rally-jobs/nova.yaml

@@ -16,45 +16,6 @@
         failure_rate:
           max: 0
 
-  EC2Servers.boot_server:
-    -
-      args:
-        flavor:
-          name: "m1.tiny"
-        image:
-          name: {{image_name}}
-      runner:
-        type: "constant"
-        times: 2
-        concurrency: 2
-      context:
-        users:
-          tenants: 3
-          users_per_tenant: 1
-      sla:
-        failure_rate:
-          max: 0
-
-  EC2Servers.list_servers:
-    -
-      runner:
-        type: "constant"
-        times: 3
-        concurrency: 3
-      context:
-        users:
-          tenants: 3
-          users_per_tenant: 1
-        ec2_servers:
-          flavor:
-            name: "m1.tiny"
-          image:
-            name: {{image_name}}
-          servers_per_tenant: 2
-      sla:
-        failure_rate:
-          max: 0
-
   Quotas.nova_update_and_delete:
     -
       args: