Wed, June 21, 2017: Linux machine security issue and reboots

To address an extremely dangerous and widespread vulnerability, we will be patching all the linux machines in the next few days.

This patch requires a reboot.

Condor users will see a slightly higher rate of job restarts as we patch and reboot the condor-only hosts. We will try to schedule patch times with people for their desktop machines, but we don't want to spend more than a few days on getting every computer patched.