tests: replace traffic_summary test with python blackbox test

tests: replace traffic_summary test with python blackbox test

Replace the shell subunit test for script/traffic_summary.pl with a
python black box test.

This involves moving the test files to more standard locations.

Signed-off-by: Gary Lockyer <gary@catalyst.net.nz>
Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Garming Sam <garming@catalyst.net.nz>
Autobuild-User(master): Douglas Bagnall <dbagnall@samba.org>
Autobuild-Date(master): Thu Aug 17 07:59:38 CEST 2017 on sn-devel-144