Delete the directory itself in deleteDirectory

common/src/main/java/ctbrec/io/IoUtils.java

@@ -55,6 +55,8 @@ public class IoUtils {
         if (!deletedAllFiles) {
             throw new IOException("Couldn't delete all files in " + directory);
         }
+
+        Files.delete(directory.toPath());
     }
 
     public static long getDirectorySize(File dir) {