dirstate: invalidate the dirstate change on transaction failure

If the change context lives inside a transaction, the change are not flushed to
disk on exit as this is delegated to the transaction. As a result we should
also delegate the part that do cleanup on failure.

The issue was caught by tests with other change, but it seems useful to fix this
as soon as possible.

mercurial/dirstate.py

@@ -204,7 +204,11 b' class dirstate:'
                         # Exception catching (and the associated `invalidate`
                         # calling) might have been called by a nested context
                         # instead of the top level one.
-                        self.write(repo.currenttransaction())
+                        tr = repo.currenttransaction()
+                        if tr is not None:
+                            abort_cb = lambda tr: self.invalidate()
+                            tr.addabort(b'dirstate', abort_cb)
+                        self.write(tr)
 
     @contextlib.contextmanager
     def changing_parents(self, repo):