[MC-65512] Pick Block on Double Red Sandstone Slab crashes the game.

See the two attached crash reports.

One happened while trying to place a red sandstone slab on another. The 2nd crash happened when I middle clicked.

java.lang.IllegalArgumentException: Cannot get property bej{name=variant, clazz=class bav, values=[stone, sandstone, wood_old, cobblestone, brick, stone_brick, nether_brick, quartz]} as it does not exist in bds{block=minecraft:stone_slab2, properties=[half, variant]}
	at bdv.b(SourceFile:112)
	at bau.a(SourceFile:117)
	at ath.j(SourceFile:821)
	at awf.j(SourceFile:146)
	at bsi.aw(SourceFile:2095)
	at bsi.r(SourceFile:1792)
	at bsi.as(SourceFile:874)
	at bsi.a(SourceFile:311)
	at net.minecraft.client.main.Main.main(SourceFile:120)

Environment

[16:13:11 INFO]: Minecraft Launcher 1.5.1 (through bootstrap 4) started on windows...
[16:13:11 INFO]: Current time is Aug 6, 2014 4:13:11 PM
[16:13:11 INFO]: System.getProperty('os.name') == 'Windows 7'
[16:13:11 INFO]: System.getProperty('os.version') == '6.1'
[16:13:11 INFO]: System.getProperty('os.arch') == 'amd64'
[16:13:11 INFO]: System.getProperty('java.version') == '1.8.0_11'
[16:13:11 INFO]: System.getProperty('java.vendor') == 'Oracle Corporation'
[16:13:11 INFO]: System.getProperty('sun.arch.data.model') == '64'