Fix potential resource leak in ConcurrentJarCreator

Author: plamentotev

src/main/java/org/codehaus/plexus/archiver/zip/ConcurrentJarCreator.java

@@ -121,6 +121,7 @@ public void writeTo(ZipArchiveOutputStream targetStream) throws IOException, Exe
         long startAt = System.currentTimeMillis();
         targetStream.close();
         zipCloseElapsed = System.currentTimeMillis() - startAt;
+        metaInfDir.close();
         manifest.close();
         directories.close();
         synchronousEntries.close();