Use testtools as the base testcase class.

Use testtools as the base unittest test case class towards to
parallelizing the test runs. Catch places where setUp and tearDown
were not being chained properly, and fix these problems.Remove
custom skip, using testtools.skip instead. Add TestResourceManager.

Part of blueprint speed-up-tempest

Change-Id: I8e7b5686b22969a0f3db96100a357c93a4d5c03f
diff --git a/tempest/tests/volume/base.py b/tempest/tests/volume/base.py
index 33bae45..de78c99 100644
--- a/tempest/tests/volume/base.py
+++ b/tempest/tests/volume/base.py
@@ -19,7 +19,7 @@
 import time
 
 import nose
-import unittest2 as unittest
+import testtools
 
 from tempest import clients
 from tempest.common.utils.data_utils import rand_name
@@ -29,7 +29,7 @@
 LOG = logging.getLogger(__name__)
 
 
-class BaseVolumeTest(unittest.TestCase):
+class BaseVolumeTest(testtools.TestCase):
 
     """Base test case class for all Cinder API tests."""
 
@@ -66,7 +66,7 @@
                                              cls.os.tenant_name)
         except exceptions.EndpointNotFound:
             cls.clear_isolated_creds()
-            raise nose.SkipTest(skip_msg)
+            raise cls.skipException(skip_msg)
 
     @classmethod
     def _get_identity_admin_client(cls):