shelve: inline shelvedfile.filename() since there are no callers outside class Differential Revision: https://phab.mercurial-scm.org/D9709

shelve: make listshelves() return shelf names instead of filenames All three callers now prefer the shelf name over the filename (already before my recent patches, two out of three callers preferred the shelf name). Differential Revision: https://phab.mercurial-scm.org/D9708