censor: accept censored revision during upgrade

They can simply be passed by as censored.

mercurial/revlog.py

@@ -3537,7 +3537,11 b' class revlog:'
 
                 sidedata = None
                 if not cachedelta:
-                    rawtext = self._revisiondata(rev)
+                    try:
+                        rawtext = self._revisiondata(rev)
+                    except error.CensoredNodeError as censored:
+                        assert flags & REVIDX_ISCENSORED
+                        rawtext = censored.tombstone
                     sidedata = self.sidedata(rev)
                 if sidedata is None:
                     sidedata = self.sidedata(rev)

tests/test-censor.t

@@ -561,10 +561,6 b' With the "abort" policy'
     - changelog
     - manifest
   
-  transaction abort!
-  rollback completed
-  abort: file censored target:613bc869fceb
-  [255]
   $ hg verify  --config censor.policy=ignore
   checking changesets
   checking manifests
@@ -598,10 +594,6 b' With the "ignore" policy'
     - changelog
     - manifest
   
-  transaction abort!
-  rollback completed
-  abort: file censored target:613bc869fceb
-  [255]
   $ hg verify --config censor.policy=ignore
   checking changesets
   checking manifests