Say in the doc that DISALLOW_CONFIG_VPN now works.

BUG:18902920
Change-Id: I761cba1f1e01fbe88f773887bf4e9233fc85cfef
diff --git a/core/java/android/os/UserManager.java b/core/java/android/os/UserManager.java
index 3dee68c..6721298 100644
--- a/core/java/android/os/UserManager.java
+++ b/core/java/android/os/UserManager.java
@@ -177,7 +177,8 @@
     /**
      * Specifies if a user is disallowed from configuring VPN.
      * The default value is <code>false</code>.
-     * This restriction has no effect in a managed profile.
+     * This restriction has an effect in a managed profile only from
+     * {@link android.os.Build.VERSION_CODES#MNC}
      *
      * <p/>Key for user restrictions.
      * <p/>Type: Boolean