remote-hg: improve branch listing

We want to show the remote heads, not the internal ones, which might
have garbage.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/remote-helpers/git-remote-hg

@@ -605,9 +605,12 @@ def do_list(parser):
     list_head(repo, cur)
 
     if track_branches:
-        for branch in repo.branchmap():
-            heads = repo.branchheads(branch)
-            if len(heads):
+        orig = peer if peer else repo
+
+        for branch, heads in orig.branchmap().iteritems():
+            # only open heads
+            heads = [h for h in heads if 'close' not in repo.changelog.read(h)[5]]
+            if heads:
                 branches[branch] = heads
 
         for branch in branches: