Fix wrong key name for jenkins client username

Change-Id: I6ddfe5c7deeb1517127d1a68c68fa13187d4b699
diff --git a/jenkins/client/init.yml b/jenkins/client/init.yml
index ef0241d..b37c48f 100644
--- a/jenkins/client/init.yml
+++ b/jenkins/client/init.yml
@@ -13,7 +13,7 @@
       master:
         host: ${_param:jenkins_master_host}
         port: ${_param:jenkins_master_port}
-        user: ${_param:jenkins_client_user}
+        username: ${_param:jenkins_client_user}
         password: ${_param:jenkins_client_password}
       plugin:
         ansicolor: {}