you can't use validate_script_output like this, it doesn't just
return a bool, it actually kills the test if the output doesn't
validate. So any time we didn't have anything in /var/tmp/abrt,
the post_fail_hook would die at that point and not upload the
contents of /var/log as we wanted it to.

Note that even script_output will kill the test if the return
code is >0. That's OK in this case, but always be careful with
these subroutines.

Run a test that fails in post-install but doesn't
produce anything in /var/tmp/abrt (you may have to artificially
break something). Check that it now uploads /var/log. I noticed
this while working on FreeIPA tests...