CI: use venv only (and not virtualenv)

It seems we used virtualenv for ceph-ansible only.

Change-Id: I7f9002283462dbe4bae3c1d7ff1dedcc4e7d01f2

tests/deploy-ceph-ansible.sh

@@ -8,7 +8,7 @@ export PYTHONUNBUFFERED=1
 
 function setup_ceph_ansible {
     # Prepare virtualenv for ceph-ansible deployment
-    virtualenv --system-site-packages ~/ceph-venv
+    python3 -m venv --system-site-packages ~/ceph-venv
     ~/ceph-venv/bin/pip install -Ir requirements.txt
     ~/ceph-venv/bin/pip install -IU selinux
 }

tests/pre.yml

@@ -31,19 +31,9 @@
           - gawk
           - python3-pip
           - python3-setuptools
-          - python3-virtualenv
           - python3-wheel
       become: true
 
-    # NOTE(hrw): On RedHat systems it is part of python3-virtualenv
-    - name: Install virtualenv on Debian systems
-      package:
-        name:
-          - virtualenv
-      become: true
-      when:
-        ansible_os_family == "Debian"
-
     - name: Ensure /tmp/logs/ dir
       file:
         path: "{{ logs_dir }}"