Install libvirt-python from source instead of a wheel

Apparently the binary installation no longer works.

Change-Id: I4ab7cf8432ccce0c3286b7ac696acfb3d4e64655

playbooks/roles/bifrost-create-vm-nodes/tasks/prepare_libvirt.yml

@@ -22,16 +22,24 @@
     - default_boot_mode != 'uefi'
     - test_vm_secure_boot | bool
 
-- name: install libvirt-python, gunicorn and lxml
+- name: install gunicorn and lxml
   include_role:
     name: bifrost-pip-install
   vars:
     package: "{{ item }}"
   loop:
-    - libvirt-python
     - gunicorn
     - lxml
 
+- name: install libvirt-python
+  include_role:
+    name: bifrost-pip-install
+  vars:
+    package: libvirt-python
+    # FIXME(dtantsur): libvirt-python 7.5.0 cannot be used when installed from
+    # a wheel, force a source installation
+    extra_args: --no-binary libvirt-python
+
 - name: configure libvirt log filters for qemu
   blockinfile:
     path: /etc/libvirt/libvirtd.conf

releasenotes/notes/libvirt-not-importable-c8e88a8ef11a1f09.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    Works around the ``libvirt module is not importable`` error by installing
+    libvirt-python from source install of a wheel.