The law still exists, but it isn't called obstruction these days. It's called 'Impeding The Progress Of An Opponent Without Contact'. It reads as follows:
"Impeding the progress of an opponent means moving into the opponent’s path to obstruct, block, slow down or force a change of direction when the ball is not within playing distance of either player."
This was debated earlier on Soccer Saturday. It was clearly a foul by Patterson, but more fool the keeper for not making more of an effort to go through him or claim the foul. Patterson certainly got away with it but it was pathetic goalkeeping.