Fix the broken build. Shame on me.

src/main/java/com/gmail/nossr50/util/Motd.java

@@ -85,7 +85,7 @@ public final class Motd {
     public static void displayXpPerks(Player player) {
         for (SkillType skill : SkillType.values()) {
             if (PerksUtils.handleXpPerks(player, 1, skill) > 1) {
-                player.sendMessage(perkPrefix + LocaleLoader.getString("Effects.Template", LocaleLoader.getString("Perks.XP.Name"), LocaleLoader.getString("Perks.XP.Desc")));
+                player.sendMessage(PERK_PREFIX + LocaleLoader.getString("Effects.Template", LocaleLoader.getString("Perks.XP.Name"), LocaleLoader.getString("Perks.XP.Desc")));
                 return;
             }
         }