Cloned from launchpad blueprint https://blueprints.launchpad.net/nova/+spec/no-stacktraces-in-logs. Description: If Nova is acting normally, we shouldn't have stack traces in our logs. It will make problem determination by admins and developers unnessessarily hard as they'll have to mentally filter out important vs. "always happens" stack traces. We should enforce this by making gate fail if after we've running all the tests successfully we find stack traces in the logs. Specification URL (additional information): None