Add missing javadoc @param for new method setObjectCountCallback()

Change-Id: I91acdc3680bde09ae5809c14460500223a410395
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/pack/PackWriter.java

@@ -391,6 +391,9 @@ public class PackWriter implements AutoCloseable {
 	 * It should be set before calling
 	 * {@link #writePack(ProgressMonitor, ProgressMonitor, OutputStream)}.
 	 *
+	 * @param callback
+	 *            the callback to set
+	 *
 	 * @return this object for chaining.
 	 * @since 4.1
 	 */

org.eclipse.jgit/src/org/eclipse/jgit/transport/BundleWriter.java

@@ -253,6 +253,9 @@ public class BundleWriter {
 	 * This callback will be passed on to
 	 * {@link PackWriter#setObjectCountCallback}.
 	 *
+	 * @param callback
+	 *            the callback to set
+	 *
 	 * @return this object for chaining.
 	 * @since 4.1
 	 */