Amend architecture defining variable

Author: MaxBed4d

etc/kayobe/stackhpc-overcloud-dib.yml

@@ -15,9 +15,7 @@ stackhpc_overcloud_dib_host_image:
   elements: "{{ stackhpc_overcloud_dib_elements }}"
   env: "{{ stackhpc_overcloud_dib_env_vars }}"
   packages: "{{ stackhpc_overcloud_dib_packages }}"
-  properties:
-    - cpu_arch: "{{ overcloud_dib_architecture }}"
-
+  architecture: "{{ overcloud_dib_architecture }}"
 
 # StackHPC overcloud DIB image name.
 stackhpc_overcloud_dib_name: "deployment_image"