Stop to use the __future__ module.

The __future__ module [1] was used in this context to ensure compatibility
between python 2 and python 3.

We previously dropped the support of python 2.7 [2] and now we only support
python 3 so we don't need to continue to use this module and the imports
listed below.

Imports commonly used and their related PEPs:
- `division` is related to PEP 238 [3]
- `print_function` is related to PEP 3105 [4]
- `unicode_literals` is related to PEP 3112 [5]
- `with_statement` is related to PEP 343 [6]
- `absolute_import` is related to PEP 328 [7]

[1] https://docs.python.org/3/library/__future__.html
[2] https://governance.openstack.org/tc/goals/selected/ussuri/drop-py27.html
[3] https://www.python.org/dev/peps/pep-0238
[4] https://www.python.org/dev/peps/pep-3105
[5] https://www.python.org/dev/peps/pep-3112
[6] https://www.python.org/dev/peps/pep-0343
[7] https://www.python.org/dev/peps/pep-0328

Change-Id: I65fb53db889afcf1a947ea61094bfab877853324

neutronclient/neutron/v2_0/__init__.py

@@ -14,8 +14,6 @@
 #    under the License.
 #
 
-from __future__ import print_function
-
 import abc
 import argparse
 import functools

neutronclient/neutron/v2_0/agentscheduler.py

@@ -14,8 +14,6 @@
 #    under the License.
 #
 
-from __future__ import print_function
-
 from neutronclient._i18n import _
 from neutronclient.neutron import v2_0 as neutronV20
 from neutronclient.neutron.v2_0 import network

neutronclient/neutron/v2_0/auto_allocated_topology.py

@@ -14,8 +14,6 @@
 #    under the License.
 #
 
-from __future__ import print_function
-
 import argparse
 
 from cliff import show

neutronclient/neutron/v2_0/bgp/dragentscheduler.py

@@ -14,8 +14,6 @@
 #    under the License.
 #
 
-from __future__ import print_function
-
 from neutronclient._i18n import _
 from neutronclient.neutron import v2_0 as neutronV20
 from neutronclient.neutron.v2_0.bgp import speaker as bgp_speaker

neutronclient/neutron/v2_0/bgp/speaker.py

@@ -14,8 +14,6 @@
 #    under the License.
 #
 
-from __future__ import print_function
-
 from neutronclient._i18n import _
 from neutronclient.common import utils
 from neutronclient.common import validators

neutronclient/neutron/v2_0/flavor/flavor.py

@@ -13,8 +13,6 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from __future__ import print_function
-
 import argparse
 
 from neutronclient._i18n import _

neutronclient/neutron/v2_0/floatingip.py

@@ -14,8 +14,6 @@
 #    under the License.
 #
 
-from __future__ import print_function
-
 import argparse
 
 from neutronclient._i18n import _

neutronclient/neutron/v2_0/fw/firewallpolicy.py

@@ -14,8 +14,6 @@
 #    under the License.
 #
 
-from __future__ import print_function
-
 import argparse
 
 from neutronclient._i18n import _

neutronclient/neutron/v2_0/lb/healthmonitor.py

@@ -14,8 +14,6 @@
 #    under the License.
 #
 
-from __future__ import print_function
-
 from neutronclient._i18n import _
 from neutronclient.neutron import v2_0 as neutronV20
 

neutronclient/neutron/v2_0/quota.py

@@ -14,8 +14,6 @@
 #    under the License.
 #
 
-from __future__ import print_function
-
 import abc
 import argparse
 

neutronclient/neutron/v2_0/router.py

@@ -14,8 +14,6 @@
 #    under the License.
 #
 
-from __future__ import print_function
-
 import argparse
 
 from oslo_serialization import jsonutils

neutronclient/osc/v2/fwaas/firewallpolicy.py

@@ -14,8 +14,6 @@
 #    under the License.
 #
 
-from __future__ import print_function
-
 import logging
 
 from osc_lib.command import command

neutronclient/shell.py

@@ -18,8 +18,6 @@
 Command-line interface to the Neutron APIs
 """
 
-from __future__ import print_function
-
 import argparse
 import inspect
 import itertools