Fix error when PAC set rapidly

Stop the broadcast from being accidentally sent when PAC is in the process
of downloading / binding local proxy.  Only send broadcast when valid port
is contained (i.e. sent by PacManager).

Bug: 11168706
Change-Id: I998711fcf0a6bd82bdef413726ec41317752a57b

services/java/com/android/server/connectivity/PacManager.java

@@ -162,7 +162,7 @@ public class PacManager {
      */
     public synchronized boolean setCurrentProxyScriptUrl(ProxyProperties proxy) {
         if (!TextUtils.isEmpty(proxy.getPacFileUrl())) {
-            if (proxy.getPacFileUrl().equals(mPacUrl)) {
+            if (proxy.getPacFileUrl().equals(mPacUrl) && (proxy.getPort() > 0)) {
                 // Allow to send broadcast, nothing to do.
                 return false;
             }