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

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

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.

--- a/mercurial/bundlerepo.py	Thu Mar 02 13:31:07 2017 +0100
+++ b/mercurial/bundlerepo.py	Thu Mar 02 14:47:03 2017 +0100
@@ -37,8 +37,8 @@
     phases,
     pycompat,
     revlog,
-    scmutil,
     util,
+    vfs as vfsmod,
 )
 
 class bundlerevlog(revlog.revlog):
@@ -50,7 +50,7 @@
         #
         # To differentiate a rev in the bundle from a rev in the revlog, we
         # check revision against repotiprev.
-        opener = scmutil.readonlyvfs(opener)
+        opener = vfsmod.readonlyvfs(opener)
         revlog.revlog.__init__(self, opener, indexfile)
         self.bundle = bundle
         n = len(self)
@@ -239,7 +239,7 @@
     def __init__(self, *args, **kwargs):
         super(bundlephasecache, self).__init__(*args, **kwargs)
         if util.safehasattr(self, 'opener'):
-            self.opener = scmutil.readonlyvfs(self.opener)
+            self.opener = vfsmod.readonlyvfs(self.opener)
 
     def write(self):
         raise NotImplementedError