This file has been seen on a few servers with the Unattended-Upgrades
flag set to 0 disabling daily unattended upgrades. Most of our servers
have this set to 1 and are fine, but let's go ahead and manage this file
directly to ensure it is always 1 and auto upgrades are enabled.
Note that previously we had been setting this via apt.conf.d/10periodic
which seems to come from the update-notifier-common package on older
systems and is now no longer used. Since that file's prefix is smaller
than 20auto-upgrades the 20auto-ugprades file installed by
unattended-upgrades overrides this value. A future update would be to
coalesce both 10periodic and 20auto-upgrades together into one config
file.
Change-Id: Ic0bdaaf881780072fda7e60ff89b60b3a07b5804
b88bc56c55