copr: followup for previous commit

roles/copr/backend/files/provision/spinup_aws_task.yml

@@ -5,7 +5,7 @@
     key_name: "{{ keypair }}"
     group: "{{ security_group }}"
     instance_type: "{{ instance_type }}"
-    image: "{{ builder_images[arch] }}"
+    image: "{{ image_name }}"
     wait: true
     region: "{{ aws_region }}"
     # both x86_64 and aarch64 arches can be allocated in us-east-1c