WORLDGUARD-3699 - Reported by elFlashor

1. Create a new region.
2. Set the fire-spread flag to DENY
3. Light a wood/netherrack/coal block with a lighter
4. Fire still spreads around blocks, even though no blocks get destroyed.

Used version: 6.1.2-SNAPSHOT;1653-65e48d1
Server version: spigot 1.9.2