GUACAMOLE-462: Ensure compatibility with 1.x extensions is maintained.

guacamole-ext/src/main/java/org/apache/guacamole/net/auth/ConnectionRecord.java

@@ -82,6 +82,8 @@ public interface ConnectionRecord extends ActivityRecord {
      * history records, such as log messages and session recordings.
      */
     @Override
-    public UUID getUUID();
+    public default UUID getUUID() {
+        return null;
+    }
 
 }