Remove migrated utils code

This commit removes all the utils code which has been migrated to
tempest-lib and updates the uses of it to point to the library instead.

Change-Id: I9207641aa91c0ea7feb8e067316fc220880c3a3b
diff --git a/tempest/api/identity/admin/v3/test_groups.py b/tempest/api/identity/admin/v3/test_groups.py
index 2c70a7c..98d1846 100644
--- a/tempest/api/identity/admin/v3/test_groups.py
+++ b/tempest/api/identity/admin/v3/test_groups.py
@@ -13,8 +13,9 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from tempest_lib.common.utils import data_utils
+
 from tempest.api.identity import base
-from tempest.common.utils import data_utils
 from tempest import test