Depreacte FileSystemUtils 0-argument contructor

Author: garydgregory

src/main/java/org/apache/commons/io/FileSystemUtils.java

@@ -242,8 +242,12 @@ public static long freeSpaceKb(final String path, final long timeout) throws IOE
 
     /**
      * Instances should NOT be constructed in standard programming.
+     *
+     * @deprecated TODO Make private in 4.0.
      */
+    @Deprecated
     public FileSystemUtils() {
+        // empty
     }
 
     /**