JS: Change back from getCountryCode() to getCountryCodeOrDefault().

That change should not have been part of r538.
Review URL: https://codereview.appspot.com/6822087

javascript/i18n/phonenumbers/phonenumberutil.js

@@ -2861,7 +2861,7 @@ i18n.phonenumbers.PhoneNumberUtil.prototype.getCountryCodeForValidRegion_ =
   if (metadata == null) {
     throw 'Invalid region code: ' + regionCode;
   }
-  return metadata.getCountryCode();
+  return metadata.getCountryCodeOrDefault();
 };