Add EXTRA_COMMAND for k8s update job

Change-Id: Id2929a87fe297b1e50c6a2cc293410c915e8d17b
diff --git a/jenkins/client/job/deploy/k8s_control.yml b/jenkins/client/job/deploy/k8s_control.yml
index 3fdef11..7e915c2 100644
--- a/jenkins/client/job/deploy/k8s_control.yml
+++ b/jenkins/client/job/deploy/k8s_control.yml
@@ -21,6 +21,10 @@
               type: string
               default: "E@k8s-ctl01.*"
               description: "Salt compound target to match nodes to be updated [*, G@osfamily:debian]."
+            EXTRA_COMMAND:
+              type: string
+              default: ""
+              description: "Extra command to run before update"
             # salt master
             SALT_MASTER_CREDENTIALS:
               type: string