bugfix: missing kernel append field in system_installer_images

tasks/_mergeimages.yml

@@ -33,7 +33,7 @@
         {%-   set retval.data = system_installer_images -%}
         {%- endif -%}
         {%- do retval.data.append(['/tmp/linux_%s_%s.gz' | format(linux_installer_distribution, _linux_dist_arch), '/tmp/%s_%s' | format(_linux_installer_kernelfile, _linux_dist_arch),
-                                              linux_installer_distribution, _linux_dist_release, _linux_dist_arch]) -%}
+                                              linux_installer_distribution, _linux_dist_release, _linux_dist_arch, ""]) -%}
         {{- retval.data -}}
   loop: "{{ system_supported_releases[linux_installer_distribution] }}"
   loop_control: