[Packaging] Don't include updates in extra.list
[Packaging] Don't include updates in extra.list

sources.list already includes updates, so adding it to extra.list
produces warnings.

Change-Id: Ie46a24df8c575d33188fa925177a85df0b2de17c

sillsdev/ci-builder-scripts,sillsdev/ci-builder-scripts,sillsdev/ci-builder-scripts