Don't undelete when unlinking a deleted shot.

attract/shots/__init__.py

@@ -244,6 +244,12 @@ def patch_shot(node_id, patch):
             node_setattr(node, key, value)
     else:
         # Remaining operations are for marking as 'in use' or 'not in use'.
+        if node.get('_deleted', False) and op == u'unlink':
+            # We won't undelete a node in response to an unlink request.
+            return pillar.api.utils.jsonify({'_deleted': True,
+                                             '_etag': node['_etag'],
+                                             '_id': node['_id']})
+
         used_in_edit = {
             u'unlink': False,
             u'relink': True,
@@ -255,9 +261,6 @@ def patch_shot(node_id, patch):
     return pillar.api.utils.jsonify(r, status=status)
 
 
-
-
-
 def assert_is_valid_patch(patch):
     """Raises an exception when the patch isn't valid."""