vfs: use 'vfs' module directly in 'mercurial.cmdutil'

Now that the 'vfs' classes moved in their own module, lets use the new module
directly. We update code iteratively to help with possible bisect needs in the
future.

mercurial/cmdutil.py

@@ -45,6 +45,7 b' from . import ('
     templatekw,
     templater,
     util,
+    vfs as vfsmod,
 )
 stringio = util.stringio
 
@@ -583,7 +584,7 b' def openrevlog(repo, cmd, file_, opts):'
             raise error.CommandError(cmd, _('invalid arguments'))
         if not os.path.isfile(file_):
             raise error.Abort(_("revlog '%s' not found") % file_)
-        r = revlog.revlog(scmutil.vfs(pycompat.getcwd(), audit=False),
+        r = revlog.revlog(vfsmod.vfs(pycompat.getcwd(), audit=False),
                           file_[:-2] + ".i")
     return r