Drop explicit dependency on python-subunit
It is no longer directly used by any test code in this repository since
we switched to stestr[1].
It is now installed as a dependency of stestr.
[1] aa6baae9e03d8cc8c0eed9b15a75e03a77ff3736
Change-Id: I07911d49a1c1d66c88d6eaa1e0f2e8183350449f
diff --git a/test-requirements.txt b/test-requirements.txt
index ebde755..924f9ae 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -2,7 +2,6 @@
coverage>=4.4.1 # Apache-2.0
flake8-import-order>=0.18.0,<0.19.0 # LGPLv3
-python-subunit>=1.0.0 # Apache-2.0/BSD
oslotest>=3.2.0 # Apache-2.0
stestr>=1.0.0 # Apache-2.0
testtools>=2.2.0 # MIT