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
(cherry picked from commit 493cbe8a85)

extraconfig/pre_network/boot_param_tasks.yaml

@@ -20,8 +20,19 @@
             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/centos/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