fix docker image name & deps

.travis.yml

@@ -2,6 +2,9 @@ language: python
 matrix:
   include:
   - python: 3.6
+    before_install:
+      - pip install tox
+      - pip install flake8
     env:
       - LABEL=docker_unit_tests
     services:
@@ -9,4 +12,4 @@ matrix:
     script:
       - make build
       - make test-tox
-      - docker run -it mozilla/vautomator-standalone python3 -m pytest ./tests/
+      - docker run -it vautomator python3 -m pytest ./tests/