Update xos-tosca to use nose2 for testing

Change-Id: I74575310d3611f75da22532f668437c302cf4a29
diff --git a/Dockerfile b/Dockerfile
index 2f6bd48..5fec234 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -12,7 +12,7 @@
 COPY ${CODE_SOURCE}/ ${CODE_DEST}/
 
 # Install dependencies
-RUN pip install -r ${CODE_DEST}/pip_requirements.txt
+RUN pip install klein==16.12.0
 
 EXPOSE 9102