Fix reference to ProxyInfo extra

Also remove unneeded null check.

Change-Id: Ic25d1087f93632a24755b284ede41d870492e25d

core/java/android/net/ProxyInfo.java

@@ -155,9 +155,6 @@ public class ProxyInfo implements Parcelable {
             mHost = source.getHost();
             mPort = source.getPort();
             mPacFileUrl = source.mPacFileUrl;
-            if (mPacFileUrl == null) {
-                mPacFileUrl = Uri.EMPTY;
-            }
             mExclusionList = source.getExclusionListAsString();
             mParsedExclusionList = source.mParsedExclusionList;
         } else {