selectivepull: fix passing heads argument multiple times

Usually `heads` are passed using kwargs but sometimes they are passed using
args (for example, during clone). In this case we set in kwargs and args
and orig call fails. This patch fixes it.

Also change the tests to cover this behaviour.

remotenames.py

@@ -133,6 +133,11 @@ def expull(orig, repo, remote, *args, **kwargs):
                 bookmarks[bookmark] = remotebookmarks[bookmark]
         else:
             heads = kwargs.get('heads') or []
+            # heads may be passed as positional args
+            if len(args) > 0:
+                if args[0]:
+                    heads = args[0]
+                args = args[1:]
             for bookmark in bookmarks:
                 heads.append(remote.lookup(remotebookmarks[bookmark]))
             kwargs['bookmarks'] = bookmarks

tests/test-selective-pull.t

@@ -97,7 +97,7 @@ Specify bookmark to pull
 
 Create second remote
   $ cd ..
-  $ hg clone -q remoterepo secondremoterepo
+  $ hg clone -q ssh://user@dummy/remoterepo secondremoterepo
   $ cd secondremoterepo
   $ hg up -q 0238718db2b1
   $ hg book master