Fix: cleaner shutdown order -- stop vpn before tunnel (tunnel is used by vpn)

SampleApps/Psibot/app/src/main/java/ca/psiphon/PsiphonTunnel.java

@@ -130,8 +130,8 @@ public class PsiphonTunnel extends Psi.PsiphonProvider.Stub {
     }
 
     public synchronized void stop() {
-        stopPsiphon();
         stopVpn();
+        stopPsiphon();
         mLocalSocksProxyPort = 0;
     }