Set test_basic_traffic as smoke test

Smoke tests cover the most basic functionality and help save time if
they do identify a problem. Test test_basic_traffic is a good candidate
to be defined as a smoke test [1]. We also set attribute "slow" [2] to
signal that the test takes a long time to run.

[1] https://docs.openstack.org/tempest/latest/HACKING.html#smoke-attribute
[2] https://docs.openstack.org/tempest/latest/HACKING.html#slow-attribute

Change-Id: I11aab764763a12e4e4434ce99ae47ab02e5b033e
1 file changed