Fixes a name collison caused by using the variable name data

diff --git a/src/controllers/FetchController.php b/src/controllers/FetchController.php
index edac3d99d..acce72f4f 100755
--- a/src/controllers/FetchController.php
+++ b/src/controllers/FetchController.php
@@ -153,10 +153,10 @@ class FetchController extends Controller implements CrawlConstants
             $message = $messages_bundle->extractSendWindow();
             $packed_data = $messages_bundle->extractReceiveWindow();
             if (!empty($packed_data)) {
-                list($byte_counts, $data) = unserialize(
+                list($byte_counts, $upload_data) = unserialize(
                     $packed_data);
                 $this->handleUploadedData($byte_counts,
-                    $data, $messages_bundle);
+                    $upload_data, $messages_bundle);
             }
         }
         if (empty($message)) {
@@ -418,23 +418,23 @@ class FetchController extends Controller implements CrawlConstants
                     unlink($filename);
                 } else {
                     $logging = "... Data received successfully\n";
-                    $data = file_get_contents($filename);
+                    $upload_data = file_get_contents($filename);
                     unlink($filename);
                     if (!$diff_origin && ($crawl_type != self::ARCHIVE_CRAWL ||
                         $arc_type == "WebArchiveBundle" || $arc_type == "")) {
                         $messages_bundle->updateReceiveWindow($sequence_number,
-                            serialize([$byte_counts, $data]));
+                            serialize([$byte_counts, $upload_data]));
                         $packed_data = $messages_bundle->extractReceiveWindow();
                         if (!empty($packed_data)) {
-                            list($byte_counts, $data) = unserialize(
+                            list($byte_counts, $upload_data) = unserialize(
                                 $packed_data);
                         } else {
-                            $data = "";
+                            $upload_data = "";
                             $byte_counts = [];
                         }
                     }
                     $this->handleUploadedData($byte_counts,
-                        $data, $messages_bundle);
+                        $upload_data, $messages_bundle);
                 }
             } else {
                 $logging = "...".(