[PATCH stable] convert: update use of deprecated bzrlib property

[Kevin Bullock]

# HG changeset patch
# User Kevin Bullock <kbullock+mercurial at ringworld.org>
# Date 1468944032 18000
#      Tue Jul 19 11:00:32 2016 -0500
# Branch stable
# Node ID a5c7375e0221a5499b38638b1c6ab72f853f287b
# Parent  754f6367122953efdc7b5539a53c99308ee90216
convert: update use of deprecated bzrlib property

The inventory property was deprecated in favor of root_inventory in bzr
2.5.0. Current version is 2.7.0.

I noticed this when testing locally on Python 2.6.9, which has warnings
turned on by default. The failure that occurs without this patch can be
seen on Python 2.7 by running with warnings enabled:

     $ PYTHONWARNINGS=::DeprecationWarning make 'test-convert-bzr*'

diff --git a/hgext/convert/bzr.py b/hgext/convert/bzr.py
--- a/hgext/convert/bzr.py
+++ b/hgext/convert/bzr.py
@@ -228,9 +228,9 @@ class bzr_source(common.converter_source
                     renaming = paths[0] != paths[1]
                     # neither an add nor an delete - a move
                     # rename all directory contents manually
-                    subdir = origin.inventory.path2id(paths[0])
+                    subdir = origin.root_inventory.path2id(paths[0])
                     # get all child-entries of the directory
-                    for name, entry in origin.inventory.iter_entries(subdir):
+                    for name, entry in origin.root_inventory.iter_entries(subdir):
                         # hg does not track directory renames
                         if entry.kind == 'directory':
                             continue