Update MissionScripting.original.lua.

We don't really even need this. Some cleanup of the replacer could just
keep the original contents in memory, but this will do for now.

resources/scripts/MissionScripting.original.lua

@@ -16,6 +16,7 @@ do
 	sanitizeModule('os')
 	sanitizeModule('io')
 	sanitizeModule('lfs')
-	require = nil
-	loadlib = nil
-end
+	_G['require'] = nil
+	_G['loadlib'] = nil
+	_G['package'] = nil
+end