Fix old UNCRAFTABLE base potion conversion

Author: PseudoKnight

src/main/java/com/laytonsmith/abstraction/enums/MCPotionType.java

@@ -26,6 +26,8 @@ public static MCPotionType valueOf(String test) throws IllegalArgumentException
 			MCVanillaPotionType oldType = MCVanillaPotionType.valueOf(test);
 			if(oldType.rename != null) {
 				return MAP.get(oldType.rename);
+			} else if(oldType == MCVanillaPotionType.UNCRAFTABLE) {
+				return null;
 			}
 			throw new IllegalArgumentException("Unknown potion type: " + test);
 		}

src/main/java/com/laytonsmith/core/ObjectGenerator.java

@@ -2021,6 +2021,9 @@ public MCPotionType legacyPotionData(CArray potionArray, Target t) {
 		} catch (IllegalArgumentException ex) {
 			throw new CREFormatException("Invalid potion type: " + potionArray.get("type", t).val(), t);
 		}
+		if(type == null) {
+			return null;
+		}
 		boolean extended = false;
 		boolean upgraded = false;
 		if(potionArray.containsKey("extended")) {