add missing nose test requirement

Signed-off-by: Mike Marchetti <mmarchetti@sandvine.com>
diff --git a/test_requirements.txt b/test_requirements.txt
index 9737615..a38d080 100644
--- a/test_requirements.txt
+++ b/test_requirements.txt
@@ -1,3 +1,4 @@
 flake8
 mock
 stdeb
+nose