Fixes distributed lock record creation issue if already exists.

Fixes #6784

src/Orchard/Tasks/Locking/Services/DistributedLockService.cs

@@ -148,9 +148,12 @@ namespace Orchard.Tasks.Locking.Services {
                     // No record matched the criteria, but at least one expired record with the specified name was found.
                     // Delete the expired records before creating a new one. In theory no more than one record can exist
                     // due to the unique key constraint on the 'Name' column, it won't hurt to work on a collection.
+                    if (records.Any()) {
                         foreach (var expiredRecord in records) {
                             repository.Delete(expiredRecord);
                         }
+                        repository.Flush();
+                    }
 
                     // No valid record existed, so we're good to create a new one.
                     Logger.Debug("No valid record was found for lock '{0}'; creating a new record.", internalName);