Use flake8/hacking instead of pep8/pyflakes.

Change-Id: Id0e447a7e66562d6ad0298619e36f752ae31adb0
Reviewed-on: https://review.openstack.org/33349
Reviewed-by: James E. Blair <corvus@inaugust.com>
Reviewed-by: Doug Hellmann <doug.hellmann@dreamhost.com>
Approved: Clark Boylan <clark.boylan@gmail.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Tested-by: Jenkins
diff --git a/tools/test-requires b/tools/test-requires
index 427ef34..ef6d24e 100644
--- a/tools/test-requires
+++ b/tools/test-requires
@@ -1,3 +1,5 @@
+hacking>=0.5.3,<0.6
+
 coverage
 nose
 nosehtmloutput