largefiles: put same 'action' object back in 'newglist' The items we put in 'newglist' are always the same as what we found in actions['g'], so let's just put the same item into the list instead of creating a new one.

largefiles: don't unnecessarily sort merge action lists The action lists returned from calculateupdates() (in merge.py) are not required to be sorted. In fact, since they result from iteration over the unordered manifest, they are unlikely to be sorted. Moreover, some of the lists are appended to after they are returned from manifestmerge(). The lists are instead sorted in applyupdates(). Therefore, let's not sort the lists generated in largefiles' overridecalculateupdates().