[dvsim.py] Fix no result displayed issue

In the Deploy.py when we assign queued_items = items
Then del queued_items[:]
It deletes the original items object as well.
I reverted the code back as I do not know if there is any better
solutions.

Signed-off-by: Cindy Chen <chencindy@google.com>
diff --git a/util/dvsim/Deploy.py b/util/dvsim/Deploy.py
index c88cb3b..45f408e 100644
--- a/util/dvsim/Deploy.py
+++ b/util/dvsim/Deploy.py
@@ -459,7 +459,7 @@
                     else:
                         dispatch_items(queued_items)
                         dispatched_items.extend(queued_items)
-                        del queued_items[:]
+                        queued_items = []
 
             # Check if we are done and print the status periodically.
             all_done &= check_if_done_and_print_status(status,