Adds missing Bluetooth as network type.

The network connection type for Bluetooth is added so
that it is possible to use Bluetooth as Hotspot during
download from the Internet.

Change-Id: If8e8a3f69821beef742bc91d7a292a091861b48b

core/java/android/app/DownloadManager.java

@@ -344,6 +344,13 @@ public class DownloadManager {
          */
         public static final int NETWORK_WIFI = 1 << 1;
 
+        /**
+         * Bit flag for {@link #setAllowedNetworkTypes} corresponding to
+         * {@link ConnectivityManager#TYPE_BLUETOOTH}.
+         * @hide
+         */
+        public static final int NETWORK_BLUETOOTH = 1 << 2;
+
         private Uri mUri;
         private Uri mDestinationUri;
         private List<Pair<String, String>> mRequestHeaders = new ArrayList<Pair<String, String>>();