Overnight I updated teijenkins.hcmc.uvic.ca from 14.04 to 14.04.01. When it came back up, after re-enabling commented-out third-party repositories in /etc/sources.list.d (tei and jenkins), I discovered that the proxying of Jenkins on port 80 was no longer working. After some investigation, I discovered that the original sites-available/jenkins configuration file was not being recognized by apache -- running sudo a2ensite jenkins resulted in "jenkins site does not exist" -- because now it needs to be called jenkins.conf. Once I'd renamed it I was able to enable it, but it took a reboot to make it work; just restarting apache wasn't enough.