cve-update: log timestamps and add force update for future time

cve-update: log timestamps and add force update for future time

CVE update is currently not working properly on autobuilder.
This improves logging for problem analysis.

Future time is something which could be reason for current autobuilder
problems since the DB was not updated for more than 3 months by now.

Signed-off-by: Peter Marko <peter.marko@siemens.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>