graph: fix sort for py3
authorJoe Guo <joeg@catalyst.net.nz>
Tue, 10 Apr 2018 03:51:34 +0000 (15:51 +1200)
committerDouglas Bagnall <dbagnall@samba.org>
Fri, 13 Apr 2018 05:27:13 +0000 (07:27 +0200)
commit6d696d61dd2b3eb144a2ccabb0f7e2cd974959b7
treef87d0beab464771a4cb5c3a11c9143636b099a10
parentfadd2cec39ab38215c36e4d996ced38b95f66d37
graph: fix sort for py3

`sorted` can not sort `None` with str in py3, use the `key` arg to fix.
Sort None as ''.

Signed-off-by: Joe Guo <joeg@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
python/samba/tests/graph.py