move openapi 3 samples to the correct folder (#3267)

samples/openapi3/server/petstore/python-flask-python2/.travis.yml

@@ -0,0 +1,14 @@
+# ref: https://docs.travis-ci.com/user/languages/python
+language: python
+python:
+  - "2.7"
+  - "3.2"
+  - "3.3"
+  - "3.4"
+  - "3.5"
+  #- "3.5-dev" # 3.5 development branch
+  #- "nightly" # points to the latest development branch e.g. 3.6-dev
+# command to install dependencies
+install: "pip install -r requirements.txt"
+# command to run tests
+script: nosetests