Revert "don't insert the same notice twice into an inbox"

This reverts commit 650074c648.

classes/Inbox.php

@@ -114,16 +114,6 @@ class Inbox extends Memcached_DataObject
             return false;
         }
 
-        $ids = unpack('N*', $inbox->notice_ids);
-
-        // bulk inserts sometimes fail and get restarted.
-        // Skip if this one has been inserted before.
-
-        if (in_array($notice_id, $ids)) {
-            // effectively successful
-            return true;
-        }
-
         $result = $inbox->query(sprintf('UPDATE inbox '.
                                         'set notice_ids = concat(cast(0x%08x as binary(4)), '.
                                         'substr(notice_ids, 1, %d)) '.