ci: integration: Bundle only failed Avocado test results

ci: integration: Bundle only failed Avocado test results

Latest versions of Avocado create 'by-status' symlink shortcuts to test
results, IOW:

 # this is the main test results directory containing all data
 $ ls <path>/avocado/job-results/latest/test-results/
 01-scripts_networks_050-transient-lifecycle.t
 02-scripts_networks_051-transient-autostart.t
 ...
 22-scripts_networks_400-guest-bandwidth.t
 by_status/

 # list only the failed tests
 $ ls -l <path>/avocado/job-results/latest/test-results/by-status/FAIL
 19-scripts_networks_360-guest-network-vepa.t ->
    <path>/avocado/job-results/latest/test-results/19-scripts_networks_360-guest-network-vepa.t

Therefore, let's bundle only the failed ones, it's going to make the
log artifacts more obvious when looking for libvirt errors.

Signed-off-by: Erik Skultety <eskultet@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>