[PATCH 4 of 4 V2] localrepo: reinstate localrepo.parents with a deprecation warning

[Pierre-Yves David]

# HG changeset patch
# User Pierre-Yves David <pierre-yves.david at fb.com>
# Date 1449386089 28800
#      Sat Dec 05 23:14:49 2015 -0800
# Node ID 4ad5faeb04fee3e86de9e9d9ae530c9dc48cbc5d
# Parent  4469287024fbad9588cb3a75daa1aa76d80d4a76
# EXP-Topic deprecationwarning
# Available At http://hg.netv6.net/marmoute-wip/mercurial/
#              hg pull http://hg.netv6.net/marmoute-wip/mercurial/ -r 4ad5faeb04fe
localrepo: reinstate localrepo.parents with a deprecation warning

The function was dropped in 3fe8cb40c9c5. This API drop brokes three of my
extensions including some critical to my workflow like tortoisehg. Lets mark
this API for death and give people time to fix their code.

diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -849,10 +849,16 @@ class localrepository(object):
     def file(self, f):
         if f[0] == '/':
             f = f[1:]
         return filelog.filelog(self.svfs, f)
 
+    def parents(self, changeid=None):
+        '''get list of changectxs for parents of changeid'''
+        msg = 'repo.parents() is deprecated, use repo[%r].parents()' % changeid
+        self.ui.deprecwarn(msg, '3.7')
+        return self[changeid].parents()
+
     def changectx(self, changeid):
         return self[changeid]
 
     def setparents(self, p1, p2=nullid):
         self.dirstate.beginparentchange()