[PATCH 4 of 5 remotenames-ext] push: move to new obsutil api

[Ryan McElroy]

# HG changeset patch
# User Ryan McElroy <rmcelroy at fb.com>
# Date 1500381662 25200
#      Tue Jul 18 05:41:02 2017 -0700
# Node ID be5e71c20437ba8200593eca46380436b926fcb8
# Parent  5797e9f25309977de7b2e3d807adc741d8d56fd2
push: move to new obsutil api

diff --git a/remotenames.py b/remotenames.py
--- a/remotenames.py
+++ b/remotenames.py
@@ -31,7 +31,7 @@ from mercurial import hg
 from mercurial import localrepo
 from mercurial import lock as lockmod
 from mercurial import namespaces
-from mercurial import obsolete
+from mercurial import obsutil
 from mercurial import repair
 from mercurial import repoview
 from mercurial import revset
@@ -911,7 +911,7 @@ def expushdiscoverybookmarks(pushop):
             msg = _('remote bookmark revision is not in local repo')
             hint = _('pull and merge or rebase or use --non-forward-move')
             raise error.Abort(msg, hint=hint)
-        foreground = obsolete.foreground(repo, [repo.lookup(old)])
+        foreground = obsutil.foreground(repo, [repo.lookup(old)])
         if repo[rev].node() not in foreground:
             msg = _('pushed rev is not in the foreground of remote bookmark')
             hint = _('use --non-forward-move flag to complete arbitrary moves')