Steam Linux: disable annoying message about ubunt-x-swat repo

[zoltor]

Hello!
At first time when I running steam on my current OS (ElementaryOS 0.2 Luna x64) steam adviced me to add ubuntu-x-swat repository for apt-get because it contains latest driver and so on (http://i.imgur.com/8WEjWz0.png). But after adding it, updating and upgrading packages from it - my system became unbootable! (It based on Ubuntu 12.04 which is not latest version).
Anyhow, I had repaired my system, commented ubuntu-x-swat repository in APT source list but annoying message about it repo appearing again at Steam client starting. How I can disable it? Did not found appropriate option in Steam settings.

p.s. There is even Steam Mobile forum exists but Steam Linux not. Why???