When a container fails, it leaves a dangling tarball which name is
based on a timestamp. Further uses of make won't clean those files,
neither calling the 'docker-clean' target.
Use the .DELETE_ON_ERROR built-in target to let make remove those
temporary tarballs in case of failure.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20180818030337.22271-1-f4bug@amsat.org>
Signed-off-by: Fam Zheng <famz@redhat.com>