From the hlds_linux mailing list:

We have released an update that rolls back the Counter-Strike: Source changes made in this last update (apart from the de_inferno changes). You need to run hldsupdatetool to get this update.

which was a reply to the message:

We have released an update to Counter-Strike: Source and the Source engine. Run the hldsupdatetool to get this update.

Testing and quality control. Yeah. Right.