abusehelper: Fix botnets fact with old ruby versions

abusehelper/lib/facter/botnets.rb

@@ -4,7 +4,7 @@ Facter.add(:botnets) do
         if File.executable?("/usr/bin/botnet")
             listcmd = "su -s /bin/sh - nobody -c '/usr/bin/botnet list'"
             output = Facter::Util::Resolution.exec(listcmd)
-            output.lines.each do |line|
+            output.each_line do |line|
                 if m = line.match(/^\[\d+\]\s+(.*\.py)/)
                     botnets << File.basename(File.dirname(m[1]))
                 end