thread: Fix crash editing thread entry with inline image

This fixes an InconsistentModelException error when editing thread
entries with inline images. The fix assumes that inline images are
re-attached when a new ThreadEntry is created and the body is copied
from the previous entry. Only the non-inline attachments need to be
moved in the update query.

include/class.thread_actions.php

@@ -165,7 +165,9 @@ JS
         }
 
         // Move the attachments to the new entry
-        $old->attachments->update(array(
+        $old->attachments->filter(array(
+            'inline' => false,
+        ))->update(array(
             'object_id' => $entry->id
         ));