[MC-122373] Skeleton killing a creeper crashes the game

The bug

When a skeleton kills a creeper, the game crashes.

Crash report

17w47b: crash-2017-11-23_15.33.48-server.txt

Description: Ticking entity

java.lang.IllegalArgumentException: bound must be positive
	at java.util.Random.nextInt(Random.java:388)
	at amm.a(SourceFile:39)
	at agb.a(SourceFile:179)
	at yy.a(SourceFile:848)
	at agn.a(SourceFile:67)
	at ahq.a(SourceFile:343)
	at ahq.H_(SourceFile:260)
	at aij.H_(SourceFile:98)
	at aqc.a(SourceFile:1564)
	at ql.a(SourceFile:704)
	at aqc.h(SourceFile:1540)
	at aqc.k(SourceFile:1422)
	at ql.k(SourceFile:537)
	at net.minecraft.server.MinecraftServer.w(SourceFile:656)
	at net.minecraft.server.MinecraftServer.v(SourceFile:584)
	at ckv.v(SourceFile:152)
	at net.minecraft.server.MinecraftServer.run(SourceFile:489)
	at java.lang.Thread.run(Thread.java:745)