Remove collections.abc backwards compatibility

The collections module moves some abstract classes into the abc
submodules in py3. While we supported older versions of python, we
needed to handle importing from either the old or new locations.

Now that we only support runtimes that include the collections.abc
module, we can remove the backwards compatibility handling we had for
the old location.

Change-Id: Idd106a8199fa586e0b34c054383d64218383c001
Signed-off-by: Sean McGinnis <sean.mcginnis@gmail.com>

cinder/cmd/manage.py

@@ -50,11 +50,7 @@
 
 """CLI interface for cinder management."""
 
-try:
+import collections.abc as collections
-    import collections.abc as collections
-except ImportError:
-    import collections
-
 import logging as python_logging
 import sys
 import time

cinder/objects/base.py

@@ -14,11 +14,7 @@
 
 """Cinder common internal object model"""
 
-try:
+from collections import abc
-    from collections.abc import Callable
-except ImportError:
-    from collections import Callable
-
 import contextlib
 import datetime
 
@@ -167,7 +163,7 @@ class CinderObjectRegistry(base.VersionedObjectRegistry):
 
         # If registering class has a callable initialization method, call it.
         if isinstance(getattr(cls, 'cinder_ovo_cls_init', None),
-                      Callable):
+                      abc.Callable):
             cls.cinder_ovo_cls_init()
 
 
@@ -578,7 +574,7 @@ class CinderObjectSerializer(base.VersionedObjectSerializer):
             entity = self._process_iterable(context, self.serialize_entity,
                                             entity)
         elif (hasattr(entity, 'obj_to_primitive') and
-              isinstance(entity.obj_to_primitive, Callable)):
+              isinstance(entity.obj_to_primitive, abc.Callable)):
             # NOTE(dulek): Backport outgoing object to the capped version.
             backport_ver = self._get_capped_obj_version(entity)
             entity = entity.obj_to_primitive(backport_ver, self.manifest)

cinder/objects/cleanable.py

@@ -13,11 +13,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-try:
+import collections.abc as collections
-    import collections.abc as collections
-except ImportError:
-    import collections
-
 import inspect
 
 import decorator

cinder/tests/unit/volume/drivers/netapp/dataontap/test_block_driver_interfaces.py

@@ -13,10 +13,7 @@
 #    under the License.
 """Mock unit tests for the NetApp block storage driver interfaces"""
 
-try:
+from collections import abc
-    from collections.abc import Callable
-except ImportError:
-    from collections import Callable
 
 from cinder.tests.unit import test
 from cinder.volume.drivers.netapp.dataontap import block_cmode
@@ -56,4 +53,4 @@ class NetAppBlockStorageDriverInterfaceTestCase(test.TestCase):
     def _get_local_functions(self, obj):
         """Get function names of an object without superclass functions."""
         return set([key for key, value in type(obj).__dict__.items()
-                    if isinstance(value, Callable)])
+                    if isinstance(value, abc.Callable)])