Opt-out for always-on VPN: rename API.

Rename the opt-out flag in AndroidManifest to
SERVICE_META_DATA_SUPPORTS_ALWAYS_ON
as directed by the API Council.

Bug: 64331776
Bug: 36650087
Test: runtest --path java/com/android/server/connectivity/VpnTest.java
Change-Id: I24326fad7a89083a2409134640bda81ee0359d08
diff --git a/core/java/android/app/admin/DevicePolicyManager.java b/core/java/android/app/admin/DevicePolicyManager.java
index d8da8c5..6f9484c 100644
--- a/core/java/android/app/admin/DevicePolicyManager.java
+++ b/core/java/android/app/admin/DevicePolicyManager.java
@@ -3938,7 +3938,7 @@
      *         {@link android.Manifest.permission#BIND_VPN_SERVICE};</li>
      *     <li>target {@link android.os.Build.VERSION_CODES#N API 24} or above; and</li>
      *     <li><i>not</i> explicitly opt out of the feature through
-     *         {@link android.net.VpnService#METADATA_SUPPORTS_ALWAYS_ON}.</li>
+     *         {@link android.net.VpnService#SERVICE_META_DATA_SUPPORTS_ALWAYS_ON}.</li>
      * </ul>
      * The call will fail if called with the package name of an unsupported VPN app.
      *