Ensure that absolutized paths from hgrc do not contain ../ segments.

tests/test-paths

@@ -0,0 +1,11 b''
+#!/bin/sh
+base=`pwd`
+hg init a
+hg clone a b
+cd a
+echo '[paths]' >> .hg/hgrc
+echo 'dupe = ../b' >> .hg/hgrc
+hg in dupe | sed "s!$base!<base>!g"
+cd ..
+hg -R a in dupe | sed "s!$base!<base>!g"
+true

tests/test-paths.out

@@ -0,0 +1,5 b''
+0 files updated, 0 files merged, 0 files removed, 0 files unresolved
+comparing with <base>/b
+no changes found
+comparing with <base>/b
+no changes found

mercurial/ui.py

@@ -204,7 +204,8 b' class ui(object):'
                     pathsitems = items
                 for n, path in pathsitems:
                     if path and "://" not in path and not os.path.isabs(path):
-                        cdata.set("paths", n, os.path.join(root, path))
+                        cdata.set("paths", n,
+                                  os.path.normpath(os.path.join(root, path)))
 
         # update verbosity/interactive/report_untrusted settings
         if section is None or section == 'ui':

tests/test-keyword.out

@@ -293,7 +293,7 b' adding file changes'
 added 1 changesets with 3 changes to 3 files
 3 files updated, 0 files merged, 0 files removed, 0 files unresolved
 % incoming
-comparing with test-keyword/Test-a/../Test
+comparing with test-keyword/Test
 searching for changes
 changeset:   1:0729690beff6
 tag:         tip