revlog: change _addrevision to return the new revision

The node is passed as argument already, so returning it is quite
pointless. The revision number on the other is useful as it decouples
the caller from the revlog internals.

Differential Revision: https://phab.mercurial-scm.org/D9880

mercurial/revlog.py

@@ -2145,7 +2145,7 b' class revlog(object):'
             dfh = self._datafp(b"a+")
         ifh = self._indexfp(b"a+")
         try:
-            return self._addrevision(
+            self._addrevision(
                 node,
                 rawtext,
                 transaction,
@@ -2158,6 +2158,7 b' class revlog(object):'
                 dfh,
                 deltacomputer=deltacomputer,
             )
+            return node
         finally:
             if dfh:
                 dfh.close()
@@ -2329,7 +2330,7 b' class revlog(object):'
         if type(rawtext) == bytes:  # only accept immutable objects
             self._revisioncache = (node, curr, rawtext)
         self._chainbasecache[curr] = deltainfo.chainbase
-        return node
+        return curr
 
     def _writeentry(self, transaction, ifh, dfh, entry, data, link, offset):
         # Files opened in a+ mode have inconsistent behavior on various