Fix rally gate test

This patch set removes extra field from rally tasks
since Watcher team has removed extra field from
watcher and python-watcherclient projects.

Change-Id: Ib1640cbe8668f56f3a3a54e9f73bb1e3e6747d79

rally-jobs/README.rst

@@ -7,7 +7,7 @@ To launch this task with configured Rally you just need to run:
 
 ::
 
-  rally task start watcher/rally-jobs/watcher.yaml
+  rally task start watcher/rally-jobs/watcher-watcher.yaml
 
 Structure
 ---------

rally-jobs/watcher-watcher.yaml

@@ -17,7 +17,6 @@
                   name: "dummy"
               strategy:
                   name: "dummy"
-              extra: {}
       sla:
         failure_rate:
           max: 0
@@ -29,7 +28,6 @@
           name: "dummy"
         strategy:
           name: "dummy"
-        extra: {}
       runner:
         type: "constant"
         times: 10
@@ -56,12 +54,10 @@
                   name: "workload_balancing"
               strategy:
                   name: "workload_stabilization"
-              extra: {}
             - goal:
                   name: "dummy"
               strategy:
                   name: "dummy"
-              extra: {}
       sla:
         failure_rate:
           max: 0