hg: jdk9/sandbox/jdk: Add api note about usage pattern

[chris.hegarty at oracle.com]

Changeset: 379b4065d315
Author:    chegar
Date:      2015-03-03 17:39 +0000
URL:       http://hg.openjdk.java.net/jdk9/sandbox/jdk/rev/379b4065d315

Add api note about usage pattern

! src/java.base/share/classes/java/io/ObjectInputStream.java