ci-config: do not use OpenStack gzipped image

In the test we should use the unzipped image, which is the one
documented.

This allows us to drop some modifications to our OpenStack instance.

Signed-off-by: Mathieu Tortuyaux <mtortuyaux@microsoft.com>

Author: tormath1

ci-automation/ci-config.env

@@ -158,7 +158,7 @@ AZURE_PARALLEL="${PARALLEL_TESTS:-20}"
 AZURE_LOCATION="${AZURE_LOCATION:-westeurope}"
 
 # -- Openstack --
-: ${OPENSTACK_IMAGE_NAME:='flatcar_production_openstack_image.img.gz'}
+: ${OPENSTACK_IMAGE_NAME:='flatcar_production_openstack_image.img'}
 OPENSTACK_PARALLEL="${PARALLEL_TESTS:-3}"
 
 # -- Brightbox --