[MC-138491] Crash when rendering a sign with the vanilla datapack disabled

The bug

The game crashes when trying to render the sign block entity when the vanilla datapack is not enabled.

Crash report

18w43c: crash-2018-10-30_20.21.37-client.txt

Description: Rendering Block Entity

java.lang.IllegalArgumentException: Cannot get property bnb{name=facing, clazz=class ev, values=[north, south, west, east]} as it does not exist in Block{minecraft:oak_sign}
	at blx.c(SourceFile:95)
	at czt.a(SourceFile:46)
	at czt.a(SourceFile:21)
	at czm.a(SourceFile:148)
	at czm.a(SourceFile:128)
	at cxu.a(SourceFile:698)
	at cxq.b(SourceFile:971)
	at cxq.a(SourceFile:878)
	at cxq.a(SourceFile:752)
	at cjk.c(SourceFile:817)
	at cjk.a(SourceFile:380)
	at net.minecraft.client.main.Main.main(SourceFile:144)