py3: use bytes() to byte-stringify Abort message in handleremotechangegroup()

contrib/python3-whitelist

@@ -41,6 +41,7 b' test-bundle2-exchange.t'
 test-bundle2-format.t
 test-bundle2-multiple-changegroups.t
 test-bundle2-pushback.t
+test-bundle2-remote-changegroup.t
 test-cappedreader.py
 test-casecollision.t
 test-cat.t

mercurial/bundle2.py

@@ -1878,7 +1878,7 b' def handleremotechangegroup(op, inpart):'
         real_part.validate()
     except error.Abort as e:
         raise error.Abort(_('bundle at %s is corrupted:\n%s') %
-            (util.hidepassword(raw_url), str(e)))
+                          (util.hidepassword(raw_url), bytes(e)))
     assert not inpart.read()
 
 @parthandler('reply:changegroup', ('return', 'in-reply-to'))