Remove image_driver_list in zun.conf
Remove image_driver_list in zun.conf

We should use the default value for image_driver_list to support
both glance and docker images.

Change-Id: I123fce57cdbd7d154d70aa8d171f946f74dd4e2f

dardelean/kolla-ansible,dardelean/kolla-ansible,dardelean/kolla-ansible