Fix pep8 violations in stress tests

This fixes pep8 failures that occur in the stress tests.
These included 3 types of failures: TEMPEST N301, N306, N201

Change-Id: I54211bea03430de4ad821096eaa5264afc4f22a3
diff --git a/stress/driver.py b/stress/driver.py
index 3032d58..c50e957 100644
--- a/stress/driver.py
+++ b/stress/driver.py
@@ -15,19 +15,18 @@
 Users pass in a description of the workload and a nova manager object
 to the bash_openstack function call"""
 
-
-import random
 import datetime
+import random
 import time
 
-
-# local imports
-from test_case import *
-import utils.util
 from config import StressConfig
-from state import ClusterState, KeyPairState, FloatingIpState, VolumeState
+from state import ClusterState
+from state import FloatingIpState
+from state import KeyPairState
+from state import VolumeState
+from test_case import *
 from tempest.common.utils.data_utils import rand_name
-
+import utils.util
 
 # setup logging to file
 logging.basicConfig(