[PATCH 3 of 9] verify: drop unnecessary check for nullid

[Martin von Zweigbergk]

# HG changeset patch
# User Martin von Zweigbergk <martinvonz at google.com>
# Date 1454435174 28800
#      Tue Feb 02 09:46:14 2016 -0800
# Node ID be9804e04dbaff78080f941b45871c611cc59c74
# Parent  ae50838573c112b79ef9ba231e168b0ca1fee6f9
verify: drop unnecessary check for nullid

In eb914541a950 (verify: filter messages about missing null manifests
(issue2900), 2011-07-13), we started ignoring nullid in the list of
manifest nodeids to check. Then, in b32a30da608d (verify: do not choke
on valid changelog without manifest, 2012-08-21), we stopped adding
nullid to the list to start with. So let's drop the left-over check
now.

diff --git a/mercurial/verify.py b/mercurial/verify.py
--- a/mercurial/verify.py
+++ b/mercurial/verify.py
@@ -235,8 +235,6 @@
         if self.havemf:
             for c, m in sorted([(c, m) for m in mflinkrevs
                         for c in mflinkrevs[m]]):
-                if m == nullid:
-                    continue
                 self.err(c, _("changeset refers to unknown manifest %s") %
                          short(m))