Fix missing or unnecessary dependencies

This fixes the following problems with current requirements and test
requirements.

- netaddr is not used

- oslo.serialization and oslo.utils are imported but are not listed in
  requirements.

This also fixes the workaround for python 2 from setup.py because
python 2 support was removed some time ago.

In addition, the described behavior of pip was already fixed in
recent versions.

Change-Id: I63a56adf73c221c8f5f725c2689ddf953f90c654

requirements.txt

@@ -1,18 +1,14 @@
 # Requirements lower bounds listed here are our best effort to keep them up to
 # date but we do not test them so no guarantee of having them all correct. If
 # you find any incorrect lower bounds, let us know or propose a fix.
-
-# The order of packages is significant, because pip processes them in the order
-# of appearance. Changing the order has an impact on the overall integration
-# process, which may cause wedges in the gate later.
-
 pbr!=2.1.0,>=2.0.0 # Apache-2.0
-netaddr>=0.7.18 # BSD
 oslo.concurrency>=3.20.0 # Apache-2.0
 oslo.config>=5.1.0 # Apache-2.0
 oslo.log>=3.30.0 # Apache-2.0
 oslo.i18n>=3.15.3 # Apache-2.0
 oslo.privsep>=1.23.0 # Apache-2.0
+oslo.serialization!=2.19.1,>=2.18.0 # Apache-2.0
+oslo.utils>=2.0.0  # Apache-2.0
 oslo.versionedobjects>=1.28.0 # Apache-2.0
 ovsdbapp>=0.12.1 # Apache-2.0
 pyroute2>=0.5.2;sys_platform!='win32' # Apache-2.0 (+ dual licensed GPL2)

setup.py

@@ -13,16 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# THIS FILE IS MANAGED BY THE GLOBAL REQUIREMENTS REPO - DO NOT EDIT
 import setuptools
 
-# In python < 2.7.4, a lazy loading of package `pbr` will break
-# setuptools if some other modules registered functions in `atexit`.
-# solution from: http://bugs.python.org/issue15881#msg170215
-try:
-    import multiprocessing  # noqa
-except ImportError:
-    pass
 
 setuptools.setup(
     setup_requires=['pbr>=2.0.0'],

test-requirements.txt

@@ -1,7 +1,3 @@
-# The order of packages is significant, because pip processes them in the order
-# of appearance. Changing the order has an impact on the overall integration
-# process, which may cause wedges in the gate later.
-
 coverage!=4.4,>=4.0 # Apache-2.0
 oslotest>=1.10.0 # Apache-2.0
 ovs>=2.9.2