unbundle: properly read head modification result from bundle2

We were reading the wrong key...

mercurial/commands.py

@@ -6475,7 +6475,7 b' def unbundle(ui, repo, fname1, *fnames, '
                 finally:
                     if tr:
                         tr.release()
-                changes = [r.get('result', 0)
+                changes = [r.get('return', 0)
                            for r in op.records['changegroup']]
                 modheads = changegroup.combineresults(changes)
             else:

tests/test-bundle2-format.t

@@ -997,6 +997,7 b' Support for changegroup'
   adding manifests
   adding file changes
   added 0 changesets with 0 changes to 3 files
+  (run 'hg update' to get a working copy)
 
 with reply
 
@@ -1125,6 +1126,7 b' Simple case where it just work: GZ'
   adding manifests
   adding file changes
   added 0 changesets with 0 changes to 3 files
+  (run 'hg update' to get a working copy)
 Simple case where it just work: BZ
 ----------------------------------
 
@@ -1211,6 +1213,7 b' Simple case where it just work: BZ'
   adding manifests
   adding file changes
   added 0 changesets with 0 changes to 3 files
+  (run 'hg update' to get a working copy)
 
 unknown compression while unbundling
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