Fix import order to comply with import ordering rules.

Fixes pep8 failures TEMPEST N306 and N301.

Change-Id: I87d6ef4058170da73ff64d4e4a4caf43f8a18046
diff --git a/tempest/services/boto/clients.py b/tempest/services/boto/clients.py
index 5fabcae..9cfe234 100644
--- a/tempest/services/boto/clients.py
+++ b/tempest/services/boto/clients.py
@@ -15,12 +15,14 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import boto
-from boto.s3.connection import OrdinaryCallingFormat
-from boto.ec2.regioninfo import RegionInfo
-from tempest.services.boto import BotoClientBase
 import urlparse
 
+import boto
+from boto.ec2.regioninfo import RegionInfo
+from boto.s3.connection import OrdinaryCallingFormat
+
+from tempest.services.boto import BotoClientBase
+
 
 class APIClientEC2(BotoClientBase):