travis.yml: Install genisoimage package

travis.yml: Install genisoimage package

The genisoimage program is required for tests/cdrom-test
tests, otherwise they are skipped. The current Travis
environments do not provide it by default, so let's
explicitly require the genisoimage package.

Signed-off-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20200110191254.11303-2-wainersm@redhat.com>
Message-Id: <20200203090932.19147-5-alex.bennee@linaro.org>