change installer images from vanilla to lts

tasks/_mergeimages.yml

@@ -9,8 +9,8 @@
   when: _linux_dist_arch == "x86" or (_linux_dist_arch | regex_search('i[0-9]86'))
 
 - set_fact:
-     _linux_installer_initrfsfile: "initramfs-vanilla"
-     _linux_installer_kernelfile: "vmlinuz-vanilla"
+     _linux_installer_initrfsfile: "initramfs-lts"
+     _linux_installer_kernelfile: "vmlinuz-lts"
 
 - name: download linux installer initrfs image file 
   get_url:
@@ -38,3 +38,4 @@
   loop: "{{ system_supported_releases[linux_installer_distribution] }}"
   loop_control:
     loop_var: _linux_dist_release
+