For ref update, we were crafting obj_dict containing just the new refs. This causes quota checks to pass because it thinks only the new refs will remain. For such checks, we need to take into account existing refs as well.

Change-Id: I592048fc66daabb2461574e7decc83b52827bde9
Closes-Bug: 1355341
Merge "For ref update, we were crafting obj_dict containing just the new refs. This causes quota checks to pass because it thinks only the new refs will remain. For such checks, we need to take into account existing refs as well."