vfs: also audit rename

vfs: also audit rename

Renaming through the vfs is not used in many places, and none of them seems to
be a security risk.

However, it is still worthwhile to run the auditing on rename file to perform
developer-warning level checks.

--- a/mercurial/vfs.py	Wed Dec 26 13:44:23 2018 +0100
+++ b/mercurial/vfs.py	Wed Dec 26 13:44:37 2018 +0100
@@ -199,6 +199,7 @@
         checkambig=True only in limited cases (see also issue5418 and
         issue5584 for detail).
         """
+        self._auditpath(dst, 'w')
         srcpath = self.join(src)
         dstpath = self.join(dst)
         oldstat = checkambig and util.filestat.frompath(dstpath)