revlog: drop the unused `_chunkcache` attribute
Apparently, some time ago, the chunk cache moved in the randomaccessfile object.
--- a/mercurial/revlog.py Tue Oct 17 04:54:22 2023 +0200
+++ b/mercurial/revlog.py Tue Oct 17 05:17:02 2023 +0200
@@ -465,8 +465,6 @@
self._revisioncache = None
# Maps rev to chain base rev.
self._chainbasecache = util.lrucachedict(100)
- # 2-tuple of (offset, data) of raw data from the revlog at an offset.
- self._chunkcache = (0, b'')
self.index = None
self._docket = None