[PATCH 3 of 3 evolve-ext] errors: add missing imports of mercurial.error

[Martin von Zweigbergk]

# HG changeset patch
# User Martin von Zweigbergk <martinvonz at google.com>
# Date 1477700706 25200
#      Fri Oct 28 17:25:06 2016 -0700
# Branch stable
# Node ID 406fdf786dfa126734afa38bb1da8050633921b7
# Parent  961b53077cabab1d8ed5e09c3eebd07ae7083ee5
errors: add missing imports of mercurial.error

diff -r 961b53077cab -r 406fdf786dfa hgext/obsolete.py
--- a/hgext/obsolete.py	Fri Oct 28 17:15:57 2016 -0700
+++ b/hgext/obsolete.py	Fri Oct 28 17:25:06 2016 -0700
@@ -13,7 +13,7 @@
 were such user.
 """
 
-from mercurial import util
+from mercurial import error
 
 try:
     from mercurial import obsolete
@@ -24,9 +24,9 @@
 import json
 
 from mercurial import cmdutil
-from mercurial import error
 from mercurial.i18n import _
 from mercurial.node import bin, nullid
+from mercurial import util
 
 
 #####################################################################
diff -r 961b53077cab -r 406fdf786dfa hgext/pushexperiment.py
--- a/hgext/pushexperiment.py	Fri Oct 28 17:15:57 2016 -0700
+++ b/hgext/pushexperiment.py	Fri Oct 28 17:25:06 2016 -0700
@@ -12,6 +12,7 @@
 from StringIO import StringIO
 
 from mercurial.i18n import _
+from mercurial import error
 from mercurial import extensions
 from mercurial import wireproto
 from mercurial import obsolete
diff -r 961b53077cab -r 406fdf786dfa hgext/simple4server.py
--- a/hgext/simple4server.py	Fri Oct 28 17:15:57 2016 -0700
+++ b/hgext/simple4server.py	Fri Oct 28 17:25:06 2016 -0700
@@ -15,6 +15,7 @@
 
 import hashlib
 import struct
+from mercurial import error
 from mercurial import util
 from mercurial import wireproto
 from mercurial import extensions