manifest: move clearcaches to manifestlog

This is part of removing all functionality from manifest.manifest so we can
delete the class entirely.

contrib/perf.py

@@ -566,7 +566,7 b' def perfmanifest(ui, repo, rev, **opts):'
     ctx = scmutil.revsingle(repo, rev, rev)
     t = ctx.manifestnode()
     def d():
-        repo.manifest.clearcaches()
+        repo.manifestlog.clearcaches()
         repo.manifestlog[t].read()
     timer(d)
     fm.end()

mercurial/manifest.py

@@ -1322,6 +1322,10 b' class manifestlog(object):'
             mancache[node] = m
         return m
 
+    def clearcaches(self):
+        self._dirmancache.clear()
+        self._revlog.clearcaches()
+
 class memmanifestctx(object):
     def __init__(self, repo):
         self._repo = repo
@@ -1593,7 +1597,3 b' class manifest(manifestrevlog):'
             self._dirlogcache[dir] = manifest(self.opener, dir,
                                               self._dirlogcache)
         return self._dirlogcache[dir]
-
-    def clearcaches(self):
-        super(manifest, self).clearcaches()
-        self._mancache.clear()