API council feedback: hide and document.

Hide isMetered() and clarify moveDatabaseFrom() docs.

Bug: 28870582, 28775585
Change-Id: Iabe63045c39ce7f662488f4224b56387c3c59519

core/java/android/net/NetworkInfo.java

@@ -334,6 +334,7 @@ public class NetworkInfo implements Parcelable {
      *
      * @return {@code true} if large transfers should be avoided, otherwise
      *         {@code false}.
+     * @hide
      */
     public boolean isMetered() {
         synchronized (this) {