Downgrade edk2-ovmf package on CentOS CI nodes

It's to workaround issue with missing support for amd-sev-es
feature by cpu used on some cloud providers.
This is actually libvirt issue, and it shouldn't fail to spawn vms in
such case. Please check bugzilla [1] for more details.
According to [1] to workaround that bug edk2-ovmf package can be
downgraded to the previous version and this is what that patch is doing.

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1961562

Change-Id: I076fa17852f38afce59107899197b4da4f36596a

.pre-commit-config.yaml

@@ -2,7 +2,7 @@
 
 repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v3.4.0
+    rev: v4.0.1
     hooks:
       - id: check-added-large-files
       - id: check-byte-order-marker
@@ -19,7 +19,7 @@ repos:
       - id: trailing-whitespace
 
   - repo: https://github.com/adrienverge/yamllint.git
-    rev: v1.26.0
+    rev: v1.26.1
     hooks:
       - id: yamllint
         files: \.(yaml|yml)$

playbooks/devstack/pre.yaml

@@ -8,5 +8,6 @@
 
 - hosts: all
   roles:
+    - {role: devstack-tobiko-centos, when: ansible_distribution == 'CentOS'}
     - role: multi-node-setup
     - role: orchestrate-devstack

roles/devstack-tobiko-centos/tasks/main.yaml

@@ -0,0 +1,14 @@
+---
+- name: Downgrade edk2-ovmf package to workaround BZ 1961558
+  become: true
+  dnf:
+    name: 'edk2-ovmf-20200602gitca407c7246bf-4.el8'
+    state: present
+    allow_downgrade: true
+
+- name: Pin edk2-ovmf version
+  become: true
+  shell: |
+    set -e
+    dnf install -y 'dnf-command(versionlock)'
+    dnf versionlock add edk2-ovmf