Bug 34924: (QA follow-up) correctly handle digest data compilation for successful...

Bug 34924: (QA follow-up) correctly handle digest data compilation for successful renewal

automatic_renewals.pl does some data compilation for digest notices that
depends on the error value returned from attempt_auto_renew. However, on
successful renewal $error is undefined. Add additional checks on value
of $success and definedness of $error to compile data accurately and
avoid warns for undefined variable

Signed-off-by: Emily Lamancusa <emily.lamancusa@montgomerycountymd.gov>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>