scmutil: reorder newly added functions for vfs support in dictionary order Definition functions for vfs support in dictionary order increases readability/maintainability, because there are functions which invoke file API: - with same name: "os.listdir" and "osutil.listdir", for example - with ambiguous names: "os.mkdir" and "util.makedirs", for example

store: rename field name from "opener" to "vfs" in internal classes for fncache These fields are used only in store module, so keeping "self.opener" for backward compatibility like as "localrepository" class is not needed.

store: rename argument name from "op"(ener) to "vfs"