largefiles: in putlfile, ensure tempfile's directory exists prior to creation Let R be a repo served by an hg daemon on a machine with an empty largefiles cache. Pushing a largefiles repo to R will result in a no-such-file-or-directory OSError because putlfile will attempt to create a temporary file in R/.hg/largefiles, which does not yet exist. This patch also adds a regression test for this scenario.