consolidate_files returns unhelpful values

[icarus-sparry]

consolidate_files sorts a linked list of files by name. It then walks the list and if the same name occurs multiple times it removes one of the duplicate names (it favors undeleted files over deleted ones, and renamed files over ones which have not been renamed). At the end it returns a pointer to the last file unless something went wrong, in which case it may return NULL.

As this is a doubly linked list, it is not a total disaster that it returns essentially the end of the list, but it would make more sense to return the start of the list. A typical use of this function is

server_manifest->files = consolidate_files(server_manifest->files);