Set the enchant buff level to 1 if it's lower than 0

Prevents issue #1006 from happening again.

If a user wants to disable SuperBreaker, they should do this using
permissions and not by setting the Enchant Buff level to zero.

src/main/java/com/gmail/nossr50/config/AdvancedConfig.java

@@ -20,7 +20,10 @@ public class AdvancedConfig extends AutoUpdateConfigLoader {
 
     /* GENERAL */
     public int getAbilityLength() { return config.getInt("Skills.General.Ability_IncreaseLevel", 50); }
-    public int getEnchantBuff() { return config.getInt("Skills.General.Ability_EnchantBuff", 5); }
+    public int getEnchantBuff() {
+        int buff = config.getInt("Skills.General.Ability_EnchantBuff", 5);
+        return (buff <= 0) ? 1 : buff;
+    }
 
     /* ACROBATICS */
     public double getDodgeChanceMax() { return config.getDouble("Skills.Acrobatics.Dodge_ChanceMax", 20.0D); }