clone: activate @ bookmark if updating to it

The message "updating bookmark @ failed!" in test-bookmarks-pushpull.t
is correct, because the changeset that the @ bookmark points to is not
pushed to the target repository.

mercurial/hg.py

@@ -418,6 +418,7 b' def clone(ui, peeropts, source, dest=Non'
                 if uprev is None:
                     try:
                         uprev = destrepo._bookmarks['@']
+                        update = '@'
                     except KeyError:
                         try:
                             uprev = destrepo.branchtip('default')

tests/test-bookmarks-pushpull.t

@@ -338,7 +338,7 b' hgweb'
   updating to branch default
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg -R cloned-bookmarks bookmarks
-     @                         1:9b140be10808
+   * @                         1:9b140be10808
      X                         1:9b140be10808
      Y                         4:c922c0139ca0
      Z                         2:0d2164f0ce0d
@@ -377,6 +377,7 b' of this test.'
   remote: adding manifests
   remote: adding file changes
   remote: added 1 changesets with 1 changes to 1 files
+  updating bookmark @ failed!
   exporting bookmark add-foo
 
   $ cd ..

tests/test-bookmarks.t

@@ -366,7 +366,7 b' test clone'
   updating to branch default
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg -R cloned-bookmarks bookmarks
-     @                         2:db815d6d32e6
+   * @                         2:db815d6d32e6
      X2                        1:925d80f479bb
      Y                         2:db815d6d32e6
      Z                         2:db815d6d32e6
@@ -384,7 +384,7 b' test clone with pull protocol'
   updating to branch default
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg -R cloned-bookmarks-pull bookmarks
-     @                         2:db815d6d32e6
+   * @                         2:db815d6d32e6
      X2                        1:925d80f479bb
      Y                         2:db815d6d32e6
      Z                         2:db815d6d32e6