Fix storage.conf setup in test-system

- Don't do it at all for the CI VM: We can use the
  VM's global Podman configuration, and use faster overlay
  instead of vfs, so let's do that.
- For the developer-run (make test-system):
  - Add graphroot and runroot paths to make the configuration minimally valid
  - Explicitly point CONTAINERS_STORAGE_CONF at the configutation
    to be certain it will get used.

Then drop the (podman pull ...) in runner.sh:_podman_reset that seemed to
previously workaround the invalid /etc/containers/storage.conf .

Signed-off-by: Miloslav Trmač <mitr@redhat.com>

contrib/cirrus/runner.sh

@@ -115,15 +115,6 @@ _run_unit() {
 _podman_reset() {
     # Ensure we start with a clean-slate
     showrun podman system reset --force
-    # WARNING WARNING WARNING WARNING
-    # Without running a container, the system tests will inexplicably
-    # fail with obscure errors/warning messages.  I have no idea why
-    # running a container after a `system reset` fixes/prevents the
-    # problem.  The failures do not reproduce when tests are run manually.
-    # So unless or until /until somebody develops a better understanding,
-    # this fix is JFM - just fakking magic.
-    # WARNING WARNING WARNING WARNING
-    showrun podman run -it --rm --entrypoint /bin/true quay.io/libpod/alpine:latest
 }
 
 _run_integration() {