Move windows requirements to requirements.txt

Commit 276028cca2 added these
requirements to setup.py from a custom build hook.  These requirements
can now be expressed in requirements.txt.  We need to move them there
so that the global requirements sync job can continue to keep setup.py
in sync with the global version.

Depends-on: I2369971d306c10dc39a1b89698cec95cf7551d07
Change-Id: I3c07c279d33f6aed46c3a97dd9ba81251e51429a

requirements.txt

@@ -36,3 +36,7 @@ oslo.serialization>=1.4.0 # Apache-2.0
 oslo.utils>=1.6.0 # Apache-2.0
 
 python-novaclient>=2.22.0
+
+# Windows-only requirements
+pywin32;sys_platform=='win32'
+wmi;sys_platform=='win32'

setup.py

@@ -1,4 +1,3 @@
-#!/usr/bin/env python
 # Copyright (c) 2013 Hewlett-Packard Development Company, L.P.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@@ -27,9 +26,4 @@ except ImportError:
 
 setuptools.setup(
     setup_requires=['pbr'],
-    pbr=True,
-    # TODO(lifeless): Once pbr supports markers in requirements.txt, move this
-    # there, so that update.py can see it.
-    extras_require={
-        ':sys_platform=="win32"': ['pywin32', 'wmi']
-    })
+    pbr=True)