Fixing handling of PPConnectionException in sample code

sample/sale/RefundSale.php

@@ -34,7 +34,7 @@ try {
 	// Refund the sale
 	// (See bootstrap.php for more on `ApiContext`)
 	$sale->refund($refund, $apiContext);
-} catch (\PPConnectionException $ex) {
+} catch (PayPal\Exception\PPConnectionException $ex) {
 	echo "Exception:" . $ex->getMessage() . PHP_EOL;
 	var_dump($ex->getData());
 	exit(1);
@@ -46,4 +46,4 @@ try {
 	<pre><?php var_dump($sale);?></pre>
 	<a href='../index.html'>Back</a>
 </body>
-</html>
+</html>