bookmarks: allow pushing active bookmark on new remote head (issue5236)

Before 'hg push -B .' on new remote head complained with:
abort: push creates new remote head ...

It was because _nowarnheads was not expanding active bookmark
name, so it didn't add active bookmark "proper" name to no
warn heads list.

mercurial/discovery.py

@@ -240,15 +240,16 b' def _oldheadssummary(repo, remoteheads, '
 
 def _nowarnheads(pushop):
     # Compute newly pushed bookmarks. We don't warn about bookmarked heads.
-
-    # internal config: bookmarks.pushing
-    newbookmarks = pushop.ui.configlist('bookmarks', 'pushing')
-
     repo = pushop.repo.unfiltered()
     remote = pushop.remote
     localbookmarks = repo._bookmarks
     remotebookmarks = remote.listkeys('bookmarks')
     bookmarkedheads = set()
+
+    # internal config: bookmarks.pushing
+    newbookmarks = [localbookmarks.expandname(b)
+                    for b in pushop.ui.configlist('bookmarks', 'pushing')]
+
     for bm in localbookmarks:
         rnode = remotebookmarks.get(bm)
         if rnode and rnode in repo:

tests/test-bookmarks-pushpull.t

@@ -690,7 +690,7 b' pushing a new bookmark on a new head doe'
   $ echo c5 > f2
   $ hg ci -Am5
   created new head
-  $ hg push -B W
+  $ hg push -B .
   pushing to http://localhost:$HGPORT/
   searching for changes
   remote: adding changesets