Replace deprecated import of ABCs from collections

ABCs in collections should be imported from collections.abc and direct
import from collections is deprecated since Python 3.3.

Closes-Bug: #1936667
Change-Id: I60679f9e78e91bce1145d899332e871dd62d3a9c

zaqar/tests/unit/storage/base.py

@@ -14,7 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import collections
+from collections import abc
 import datetime
 import hashlib
 import json
@@ -832,7 +832,7 @@ class MessageControllerTest(ControllerBaseTest):
         res = self.controller.bulk_get(queue_name, message_ids,
                                        project=self.project)
 
-        self.assertIsInstance(res, collections.Iterable)
+        self.assertIsInstance(res, abc.Iterable)
         self.assertEqual([], list(res))