Use FTB_DIR for log4j2 patched files...hypothetically

[itzg]

Resolves #2690

but it doesn't make a difference since Forge is not one of the conditions for patching

docker-minecraft-server/scripts/start-finalExec

Lines 60 to 75 in f3bec94

	# Patch Log4j remote code execution vulnerability
	# See https://www.minecraft.net/en-us/article/important-message--security-vulnerability-java-edition
	if versionLessThan 1.7; then
	: # No patch required here.
	elif isFamily VANILLA && versionLessThan 1.12; then
	patchLog4jConfig log4j2_17-111.xml https://launcher.mojang.com/v1/objects/dd2b723346a8dcd48e7f4d245f6bf09e98db9696/log4j2_17-111.xml
	elif isFamily VANILLA && versionLessThan 1.17; then
	patchLog4jConfig log4j2_112-116.xml https://launcher.mojang.com/v1/objects/02937d122c86ce73319ef9975b58896fc1b491d1/log4j2_112-116.xml
	# See https://purpurmc.org/docs/Log4j/
	elif isType PURPUR && versionLessThan 1.17; then
	patchLog4jConfig purpur_log4j2_1141-1165.xml https://purpurmc.org/docs/xml/purpur_log4j2_1141-1165.xml
	elif isType PURPUR && versionLessThan 1.18.1; then
	patchLog4jConfig purpur_log4j2_117.xml https://purpurmc.org/docs/xml/purpur_log4j2_117.xml
	elif versionLessThan 1.18.1; then
	useFallbackJvmFlag=true
	fi

and CreeperHost's log4jpatcher jar was already getting applied.