fix: purging old asset revisions on large sites never completes

docs/changelog/7.x.x.txt

@@ -1,6 +1,7 @@
 7.4.9
  - fix: Bug that did not allow Calendar Update Feeds workflow activity to 
    complete
+ - fix: purging old asset revisions on large sites never completes
 
 7.4.8
  - fix: Syndicated Content doesn't display all items with multiple feeds in interleaved mode

lib/WebGUI/Workflow/Activity/PurgeOldAssetRevisions.pm

@@ -84,8 +84,7 @@ sub execute {
 
     # figure out if we left off somewhere
     my $lastRunVersion = $instance->getScratch("purgeOldAssetsLastRevisionDate");
-    my $suspectDate = time() - $self->get("purgeAfter");
-    $suspectDate = ($suspectDate > $lastRunVersion) ? $suspectDate : $lastRunVersion;
+    my $suspectDate = ($lastRunVersion > 0) ? $lastRunVersion : (time() - $self->get("purgeAfter"));
 
     # the query to find old revisions
     my $sth = $session->db->read("select assetData.assetId,asset.className,assetData.revisionDate from asset