[CORD-2460]
Update and fix build documentation, fix variables with new TOSCA engine

Change-Id: I21b5e3aa2abda0111a72d1a994140ab2894296ce
diff --git a/roles/epc-synced/tasks/main.yml b/roles/epc-synced/tasks/main.yml
index 996a069..d31a3dc 100644
--- a/roles/epc-synced/tasks/main.yml
+++ b/roles/epc-synced/tasks/main.yml
@@ -20,7 +20,7 @@
   uri:
     url: http://localhost/xosapi/v1/{{ item }}
     user: "{{ xos_admin_user }}"
-    password: "{{ xos_admin_pass }}"
+    password: "{{ head_xos_admin_pass }}"
     return_content: yes
   register: result
   until: result.json["items"] and result.json["items"][0]["backend_status"] == "OK"