vfs: simplify path audit disabling in stream clone

The whole 'mustaudit' API is quite complex compared to its actual usage by its
unique user in stream clone.

Instead we add a "auditpath" parameter to 'vfs.__call_'. The stream clone code
then explicitly open files with path auditing disabled.

The 'mustaudit' API will be cleaned up in the next changeset.

mercurial/streamclone.py

@@ -225,10 +225,11 b' def generatev1(repo):'
                 # partially encode name over the wire for backwards compat
                 yield '%s\0%d\n' % (store.encodedir(name), size)
                 if size <= 65536:
-                    with svfs(name, 'rb') as fp:
+                    with svfs(name, 'rb', auditpath=False) as fp:
                         yield fp.read(size)
                 else:
-                    for chunk in util.filechunkiter(svfs(name), limit=size):
+                    data = svfs(name, auditpath=False)
+                    for chunk in util.filechunkiter(data, limit=size):
                         yield chunk
         finally:
             svfs.mustaudit = oldaudit

mercurial/vfs.py

@@ -320,7 +320,8 b' class vfs(abstractvfs):'
         os.chmod(name, self.createmode & 0o666)
 
     def __call__(self, path, mode="r", text=False, atomictemp=False,
-                 notindexed=False, backgroundclose=False, checkambig=False):
+                 notindexed=False, backgroundclose=False, checkambig=False,
+                 auditpath=True):
         '''Open ``path`` file, which is relative to vfs root.
 
         Newly created directories are marked as "not to be indexed by
@@ -344,6 +345,7 b' class vfs(abstractvfs):'
         only for writing), and is useful only if target file is
         guarded by any lock (e.g. repo.lock or repo.wlock).
         '''
+        if auditpath:
         if self._audit:
             r = util.checkosfilename(path)
             if r: