rebase: fix working copy location after a --collapse (issue4080)

Rebasing with --collapse would leave the working copy on the parent of the
collapsed commit, instead of on the collapsed commit.  This fixes that.  Also
fixes a few tests that already covered this area but had bad data.

This also fixes issue3716 where bookmarks are not kept across rebases with
--collapse. I updated the test to cover that case as well.

hgext/rebase.py

@@ -346,6 +346,9 b' def rebase(ui, repo, **opts):'
                 commitmsg = ui.edit(commitmsg, repo.ui.username())
             newrev = concludenode(repo, rev, p1, external, commitmsg=commitmsg,
                                   extrafn=extrafn, editor=editor)
+            for oldrev in state.iterkeys():
+                if state[oldrev] > nullmerge:
+                    state[oldrev] = newrev
 
         if 'qtip' in repo.tags():
             updatemq(repo, state, skipped, **opts)

tests/test-rebase-collapse.t

@@ -57,11 +57,11 b' Rebasing B onto H and collapsing changes'
   saved backup bundle to $TESTTMP/a1/.hg/strip-backup/*-backup.hg (glob)
 
   $ hg tglogp
-  o  5:secret 'Collapsed revision
+  @  5:secret 'Collapsed revision
   |  * B
   |  * C
   |  * D'
-  @  4:draft 'H'
+  o  4:draft 'H'
   |
   | o  3:draft 'G'
   |/|
@@ -737,12 +737,13 b' Test collapsing changes that add then re'
   $ touch b
   $ hg commit -Am b
   adding b
+  $ hg book foo
   $ hg rebase -d 0 -r "1::2" --collapse -m collapsed
   saved backup bundle to $TESTTMP/collapseaddremove/.hg/strip-backup/*-backup.hg (glob)
-  $ hg tglog
-  o  1: 'collapsed'
+  $ hg log -G --template "{rev}: '{desc}' {bookmarks}"
+  @  1: 'collapsed' foo
   |
-  @  0: 'base'
+  o  0: 'base'
   
   $ hg manifest --rev tip
   b

tests/test-rebase-detach.t

@@ -329,11 +329,11 b' Verify that target is not selected as ex'
   saved backup bundle to $TESTTMP/a6/.hg/strip-backup/*-backup.hg (glob)
 
   $ hg tglog
-  o  8: 'Collapsed revision
+  @  8: 'Collapsed revision
   |  * I
   |  * Merge
   |  * J'
-  @  7: 'H'
+  o  7: 'H'
   |
   | o  6: 'G'
   |/|