atmos: fix everlasting fires

Fires were checking against a non-reduced air sample for existance, so
the reduced sample wasn't working in zburn when it failed the check.
Also fixed volatilefuel not being scaled in the phoron reagent.

Signed-off-by: Mloc-Argent <colmohici@gmail.com>

code/modules/reagents/Chemistry-Reagents.dm

@@ -1581,14 +1581,14 @@ datum
 				var/turf/the_turf = get_turf(O)
 				var/datum/gas_mixture/napalm = new
 				var/datum/gas/volatile_fuel/fuel = new
-				fuel.moles = 5
+				fuel.moles = volume
 				napalm.trace_gases += fuel
 				the_turf.assume_air(napalm)
 			reaction_turf(var/turf/T, var/volume)
 				src = null
 				var/datum/gas_mixture/napalm = new
 				var/datum/gas/volatile_fuel/fuel = new
-				fuel.moles = 5
+				fuel.moles = volume
 				napalm.trace_gases += fuel
 				T.assume_air(napalm)
 				return