Convert scenario tests to use global CONF object

This commit takes all the uses of config in the scenario tests and
converts them to use the global CONF object.

Partially implements bp config-cleanup

Change-Id: I1bac686587f1705901b653b07300077623ba9f21
diff --git a/tempest/scenario/test_swift_basic_ops.py b/tempest/scenario/test_swift_basic_ops.py
index 5892e1e..b367f7f 100644
--- a/tempest/scenario/test_swift_basic_ops.py
+++ b/tempest/scenario/test_swift_basic_ops.py
@@ -15,10 +15,13 @@
 
 
 from tempest.common.utils.data_utils import rand_name
+from tempest import config
 from tempest.openstack.common import log as logging
 from tempest.scenario import manager
 from tempest.test import services
 
+CONF = config.CONF
+
 LOG = logging.getLogger(__name__)
 
 
@@ -39,7 +42,7 @@
     def setUpClass(cls):
         cls.set_network_resources()
         super(TestSwiftBasicOps, cls).setUpClass()
-        if not cls.config.service_available.swift:
+        if not CONF.service_available.swift:
             skip_msg = ("%s skipped as swift is not available" %
                         cls.__name__)
             raise cls.skipException(skip_msg)