Handle generating grub config for EFI partitions

The default overcloud-full image uses grub config path
/boot/grub2/grub.cfg however images with EFI boot partitions use grub
config path /boot/efi/EFI/redhat/grub.cfg.

This means for EFI based images, persisting kernel boot args is
currently broken. This change fixes this by checking a known list of
grub.cfg paths and regenerating the config for each file which already
exists.

Change-Id: I9ef130a3f437c82e9e3ec2f2bc82df3ea45c410f
Closes-Bug: #1877215

tripleo_ansible/roles/tripleo_kernel/tasks/kernelargs.yml

@@ -31,8 +31,18 @@
         dest: /etc/default/grub
         line: 'GRUB_CMDLINE_LINUX="${GRUB_CMDLINE_LINUX:+$GRUB_CMDLINE_LINUX }${TRIPLEO_HEAT_TEMPLATE_KERNEL_ARGS}"'
         insertafter: '^TRIPLEO_HEAT_TEMPLATE_KERNEL_ARGS.*'
-    - name: Generate grub config file
-      command: grub2-mkconfig -o /boot/grub2/grub.cfg
+    - name: Check grub config paths
+      stat:
+        path: "{{ item }}"
+      register: grub_stat
+      loop:
+        - /boot/grub2/grub.cfg
+        - /boot/efi/EFI/redhat/grub.cfg
+        - /boot/efi/EFI/fedora/grub.cfg
+    - name: Generate grub config
+      command: "grub2-mkconfig -o {{ item.stat.path }}"
+      when: item.stat.exists|bool
+      loop: "{{ grub_stat.results }}"
     - name: Set reboot required fact
       set_fact:
         reboot_required: true