Uninstall ansible-base package only if exists

We have the list of package installed, so its nice to decide when we
can skip the task.

TrivialFix

Signed-off-by: Maksim Malchuk <maksim.malchuk@gmail.com>
Change-Id: I4884cccf8a54f6c5af37f0ee418bb3821dc87091

ansible/roles/kolla-ansible/tasks/install.yml

@@ -81,6 +81,7 @@
         state: absent
         virtualenv: "{{ kolla_ansible_venv }}"
         virtualenv_python: "{{ kolla_ansible_venv_python }}"
+      when: "'ansible-base' in pip_packages.packages[kolla_ansible_pip]"
   vars:
     kolla_ansible_pip: "{{ kolla_ansible_venv }}/bin/pip"