Tweak to allow FeedDocumentBundle's between version 3 and 4 to be migrated

diff --git a/src/executables/ArcTool.php b/src/executables/ArcTool.php
index cded12a3a..ab72c1c01 100755
--- a/src/executables/ArcTool.php
+++ b/src/executables/ArcTool.php
@@ -1138,12 +1138,14 @@ class ArcTool extends DictionaryUpdater implements CrawlConstants
     public function migrateIndexArchive($archive_path, $number_of_processes = 1)
     {
         $archive_type = $this->getArchiveKind($archive_path);
-        if ($archive_type == "IndexDocumentBundle") {
+        if (in_array($archive_type, ["FeedDocumentBundle",
+            "IndexDocumentBundle"])) {
             $version = IndexManager::getVersion($archive_path);
             if ($version < "4.0") {
                 echo "Checking if bundle upgradable...\n";
                 echo "--------------------------------\n";
-                echo "...IndexDocumentBundle Version $version detected!\n";
+                echo "...Feed or IndexDocumentBundle Version $version ".
+                    "detected!\n";
                 echo "...Upgrading bundle to version ".
                     IndexDocumentBundle::DEFAULT_VERSION . "...\n";
                 $this->migrateIndexDocument($archive_path,