Switch all uses of ConfigParser to import from six

As part of enabling python3 support in tempest we need to be able to
handle ConfigParser usage in both python2 and python3. Six provies a
compat layer for doing this, so this commit moves all uses of
ConfigParser to get it through six.

Change-Id: Ie4a788dc9b9151557e9f197fb48f3225c39de89f
diff --git a/tempest/services/botoclients.py b/tempest/services/botoclients.py
index 95c05d7..ede464f 100644
--- a/tempest/services/botoclients.py
+++ b/tempest/services/botoclients.py
@@ -13,13 +13,13 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import ConfigParser
 import contextlib
 import types
 
 import boto
 import boto.ec2
 import boto.s3.connection
+from six.moves import configparser as ConfigParser
 from six.moves.urllib import parse as urlparse
 from tempest_lib import exceptions as lib_exc