Add posibility to set slave agent port

Related-PROD: https://mirantis.jira.com/browse/PROD-21891

Change-Id: Id61042e2f197a1bfb70dc693452584938d2cc118
diff --git a/metadata/service/master/single.yml b/metadata/service/master/single.yml
index 3a8a82e..060a10a 100644
--- a/metadata/service/master/single.yml
+++ b/metadata/service/master/single.yml
@@ -6,6 +6,7 @@
   jenkins:
     master:
       enabled: true
+      slave_agent_port: 54906
       sudo: false
       mode: "NORMAL"
       http: