manifest: use public API for obtaining storage object

We should not be accessing private attributes on the manifestlog,
since its behavior is governed by an interface.

Differential Revision: https://phab.mercurial-scm.org/D4392

mercurial/manifest.py

@@ -1317,7 +1317,7 b' class manifestrevlog(object):'
             self = manifestrevlogref()
             if repo is None or self is None:
                 return
-            if repo.manifestlog._revlog is not self:
+            if repo.manifestlog.getstorage(b'') is not self:
                 # there's a different manifest in play now, abort
                 return
             self._fulltextcache.write()
@@ -1583,7 +1583,7 b' class memmanifestctx(object):'
         self._manifestdict = manifestdict()
 
     def _storage(self):
-        return self._manifestlog._revlog
+        return self._manifestlog.getstorage(b'')
 
     def new(self):
         return memmanifestctx(self._manifestlog)
@@ -1619,7 +1619,7 b' class manifestctx(object):'
         #self.linkrev = store.linkrev(rev)
 
     def _storage(self):
-        return self._manifestlog._revlog
+        return self._manifestlog.getstorage(b'')
 
     def node(self):
         return self._node
@@ -1689,7 +1689,7 b' class memtreemanifestctx(object):'
         self._treemanifest = treemanifest()
 
     def _storage(self):
-        return self._manifestlog._revlog
+        return self._manifestlog.getstorage(b'')
 
     def new(self, dir=''):
         return memtreemanifestctx(self._manifestlog, dir=dir)