Allow Packer logfile path to be set

Author: m-bull

roles/image_build/tasks/main.yml

@@ -63,7 +63,7 @@
   environment:
     ANSIBLE_CONFIG: "{{ ansible_cfg_file.path }}"
     PACKER_LOG: 1
-    PACKER_LOG_PATH: "/tmp/packer-build.log"
+    PACKER_LOG_PATH: "{{ lookup('ansible.builtin.env', 'PACKER_LOG_PATH', default='/tmp/packer-build.log') }}"
 
 - name: Parse packer-manifest.json
   set_fact: