MASSEMBLY-754 Fixed NPE when missing folder

Author: krosenvold

src/main/java/org/codehaus/plexus/archiver/tar/TarArchiver.java

@@ -492,7 +492,7 @@ protected void cleanUp()
         throws IOException
     {
         super.cleanUp();
-        tOut.close();
+        IOUtil.close( tOut );
     }
 
     protected void close()