Update pip_install role and work around OVH nested-virt issues

This patch combines the following patches in the hope
that these crucial fixes together may pass both check
and gate pipelines more successfully than just the first
on its own.

- https://review.openstack.org/558229
- https://review.openstack.org/558878

Change-Id: Id2e80b92a703bf543d309d6b2eb4df9bb377d24d

ansible-role-requirements.yml

@@ -9,7 +9,7 @@
 - name: pip_install
   scm: git
   src: https://git.openstack.org/openstack/openstack-ansible-pip_install
-  version: c68db4e674e744f4e75841de801731f3de5da8fa
+  version: 4aeb55be0b6de43b53e4081bc0065da76d6a2589
 - name: galera_client
   scm: git
   src: https://git.openstack.org/openstack/openstack-ansible-galera_client

tests/roles/bootstrap-host/tasks/prepare_aio_config.yml

@@ -62,12 +62,19 @@
     path: /etc/nodepool
   register: nodepool_dir
 
+# OVH nodepool nodes have an issue which causes nested virt
+# instances to crash with a hardware error, then a dump.
+# We therefore detect whether we're running on OVH and
+# force it to use qemu instead.
 - name: Discover the OpenStack-Infra mirrors
   shell: |
     source /etc/ci/mirror_info.sh
     NODEPOOL_OVERRIDES="/etc/openstack_deploy/user_openstackci.yml"
     echo "uca_apt_repo_url: '${NODEPOOL_UCA_MIRROR}'" >> ${NODEPOOL_OVERRIDES}
     echo "openstack_hosts_centos_mirror_url: '${NODEPOOL_CENTOS_MIRROR}'" >> ${NODEPOOL_OVERRIDES}
+    if [[ ${NODEPOOL_PYPI_MIRROR} == *.ovh.* ]]; then
+      echo "nova_virt_type: 'qemu'" >> ${NODEPOOL_OVERRIDES}
+    fi
   args:
     executable: /bin/bash
   when: