Remove usage of d2to1

d2to1 pulls in setuptools, which trips the unhappy bugs with setuptools
updating. Move past that and just use new pbr.

Change-Id: I2609eda10ed781116940c3607ff85a14fc4b7f58

requirements.txt

@@ -1,5 +1,4 @@
-d2to1>=0.2.10,<0.3
-pbr>=0.5,<0.6
+pbr>=0.5.21,<1.0
 
 argparse
 PyYAML

setup.cfg

@@ -19,10 +19,6 @@ classifier =
 [pbr]
 warnerrors = True
 
-[global]
-setup-hooks =
-    pbr.hooks.setup_hook
-
 [entry_points]
 console_scripts =
     zuul-server = zuul.cmd.server:main

setup.py

@@ -17,5 +17,5 @@
 import setuptools
 
 setuptools.setup(
-    setup_requires=['d2to1', 'pbr'],
-    d2to1=True)
+    setup_requires=['pbr'],
+    pbr=True)