Deprecate CONNECTIVITY_ACTION.

That was its destiny.
Use NetworkCallbacks instead.

Test: runtest frameworks-net, but this is only doc changes
Change-Id: I3d68dbf817de92c66d899a7cc4519c5639e4c049
diff --git a/core/java/android/net/ConnectivityManager.java b/core/java/android/net/ConnectivityManager.java
index 6848ae1..2e70132 100644
--- a/core/java/android/net/ConnectivityManager.java
+++ b/core/java/android/net/ConnectivityManager.java
@@ -112,8 +112,14 @@
      * <p/>
      * For a disconnect event, the boolean extra EXTRA_NO_CONNECTIVITY
      * is set to {@code true} if there are no connected networks at all.
+     *
+     * @deprecated apps should use the more versatile {@link #requestNetwork},
+     *             {@link #registerNetworkCallback} or {@link #registerDefaultNetworkCallback}
+     *             functions instead for faster and more detailed updates about the network
+     *             changes they care about.
      */
     @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
+    @Deprecated
     public static final String CONNECTIVITY_ACTION = "android.net.conn.CONNECTIVITY_CHANGE";
 
     /**