rename sahara-tests to sahara_tests in setup.cfg
rename sahara-tests to sahara_tests in setup.cfg

In setup.cfg, sahara-tests module is given but in project tree
module name is sahara_tests. It needs to be changed to sahara_tests

Change-Id: I6fa70b148b4a15fbf0f21672730694d8028450ef

openstack/sahara-tests,openstack/sahara-scenario,openstack/sahara-scenario,openstack/sahara-tests,openstack/sahara-tests,openstack/sahara-tests,openstack/sahara-scenario