[reproducer] Merge extra_variable_files into reproducer-variables.yml for PreMetal

PreMetal provisions hosts from the main branch, generating
reproducer-variables.yml with base scenario vars. During the actual
Zuul job, overwrite_zuul_vars.yml only merges zuul_vars.yaml into
reproducer-variables.yml, ignoring extra_variable_files entirely.

This means any scenario override passed via extra_variable_files
is silently lost on the controller. The base values from PreMetal
provisioning win, causing jobs to run the wrong test plan.

Iteratively merge each extra_variable_files entry into
reproducer-variables.yml before the zuul_vars.yaml merge, preserving
the correct precedence: base < extra_variable_files < zuul_vars.

Signed-off-by: Samuel Rac <srac@redhat.com>

Author: srac0

roles/reproducer/tasks/overwrite_zuul_vars.yml

@@ -40,6 +40,18 @@
         dest: /usr/local/bin/merge_yaml_override
         mode: "0755"
 
+    - name: Merge extra variable files into reproducer-variables.yml
+      when: extra_variable_files is defined
+      ansible.builtin.shell: >
+        python3 /usr/local/bin/merge_yaml_override
+        {{ temp_reproducer_var_path }}
+        {{ item }} >
+        {{ temp_merged_reproducer_var_path }} &&
+        cp {{ temp_merged_reproducer_var_path }}
+        {{ temp_reproducer_var_path }}
+      loop: "{{ extra_variable_files }}"
+      no_log: "{{ cifmw_nolog | default(true) | bool }}"
+
     - name: Execute merge script
       ansible.builtin.shell: >
         python3 /usr/local/bin/merge_yaml_override