[Packaging] Fix deps for win32

- Fixed trying to install py2-ipaddress breaking on Python3.
- Add wheel universal option so Py2 and Py3 wheel built.

requirements.txt

@@ -7,7 +7,7 @@ mako
 chardet
 six
 setproctitle
-pywin32; sys.platform == 'win32'
-py2-ipaddress; sys.platform == 'win32'
-certifi; sys.platform == 'win32'
+pywin32; sys_platform == 'win32'
+py2-ipaddress; sys_platform == 'win32' and python_version == '2'
+certifi; sys_platform == 'win32'
 zope.interface>=4.4.2

setup.cfg

@@ -1,3 +1,6 @@
+[bdist_wheel]
+universal = 1
+
 [build_docs]
 source-dir = docs/source
 build-dir = docs/build

setup.py

@@ -547,9 +547,9 @@ install_requires = [
     'chardet',
     'six',
     'setproctitle',
-    "pywin32; sys.platform == 'win32'",
-    "py2-ipaddress; sys.platform == 'win32'",
-    "certifi; sys.platform == 'win32'",
+    "pywin32; sys_platform == 'win32'",
+    "py2-ipaddress; sys_platform == 'win32' and python_version == '2'",
+    "certifi; sys_platform == 'win32'",
     'zope.interface',
 ]
 tests_require = ['pytest', 'pytest-twisted']