setup: add hgext.lfs to list of Python packages

This is needed for lfs to get installed. Probably could stand to go
into an earlier patch, but I just want to get this stuff pushed.

setup.py

@@ -767,7 +767,7 b" packages = ['mercurial',"
             'mercurial.thirdparty.attr',
             'hgext', 'hgext.convert', 'hgext.fsmonitor',
             'hgext.fsmonitor.pywatchman', 'hgext.highlight',
-            'hgext.largefiles', 'hgext.zeroconf', 'hgext3rd',
+            'hgext.largefiles', 'hgext.lfs', 'hgext.zeroconf', 'hgext3rd',
             'hgdemandimport']
 
 common_depends = ['mercurial/bitmanipulation.h',