[1.9] South facing pistons have an incorrect texture.

Partner Rank: 4
Verification Builds: New beta 1.9
Summary: Pistons placed facing south have their top texture shifted so there appears to be two heads.
Repro Steps:
1. Create a new world
2. Place a piston while looking north, such that the head of the piston faces south.
Observed Results: The texture on the top of the piston shows two heads.
Expected Results: The texture on top of the piston matches the other sides.
Screenshots/Videos attached: Yes, an image of the issue.