localrepo: add "vfs" fields to "localrepository" for migration from "opener" As a part of migration to vfs, this patch adds "vfs" fields to "localrepository" class. This allows new codes to access current "opener" objects related to repositories via "vfs" fields, so patches referring to "vfs" will replace referring to "opener" in time. This patch also adds initializations for "vfs" fields to "statichttprepository" class derived from it, because its constructor doesn't invoke the constructor of "localrepository", so "vfs" fields should be initialized explicitly as same as "opener" fields: it has no working directory, so "wvfs" field is not added.