Fix storing the wrong value of mLockdown in setting

When user is stopped, the Vpn#onUserStopped() will be called and
the value of mLockdown will be set to false then store into
This is a wrong behavior because user doesn't change it, so for
this kind of case, there is no need to store the value of
mLockdown in setting.
In fact, there is no need to call Vpn#saveAlwaysOnPackage() when
user is stopped because there is nothing changed.

Bug: 168500792
Test: atest FrameworksNetTests
Change-Id: Ie85a347216614b7873bfdf199165d89527ada3a8
diff --git a/services/core/java/com/android/server/connectivity/ b/services/core/java/com/android/server/connectivity/
index d51e1f7..8adb7f3 100644
--- a/services/core/java/com/android/server/connectivity/
+++ b/services/core/java/com/android/server/connectivity/
@@ -1138,7 +1138,7 @@
     public synchronized void onUserStopped() {
         // Switch off networking lockdown (if it was enabled)
-        setLockdown(false);
+        setVpnForcedLocked(false);
         mAlwaysOn = false;