Py3: fix an error when adding two `dict_items`

Fix the following error "TypeError: unsupported operand type(s) for +:
'dict_items' and 'dict_items'" on Python3.

This is the only occurence of this pattern, as far as I can tell.

Change-Id: I3d926c56648f8ae0b28abfd8ca1806134ba3df41
1 file changed