hg_delta_editor: detect new branches issued from non-branch directories This fix solves the following case: let's /dumb/layout/project be an existing project. To normalize the trunk/branches/tags layout, people may do: $ mkdir /project $ mv /dumb/layout/project /project/project # Oups, should have been trunk! $ mv /project/project /project/trunk trunk creation was ignore because: - update_branch_map() sees it come from a non-branch copy source and ignores it (case #3). - since it is not in self.branches, add_directory() ignores the non-existing path. Then trunk is left uninitialized. To solve this, we allow update_branch_map() to detect branches copied from non-canonical locations.