Correct module for --cov

.travis.yml

@@ -17,7 +17,7 @@ install:
   - python setup.py install
 script:
   - docker build -t clair_singularity .
-  - docker run -v $TRAVIS_BUILD_DIR:/app --privileged --name clair-singularity --link clair:clair clair_singularity pytest tests/ --cov clair-singularity --cov-report term-missing
+  - docker run -v $TRAVIS_BUILD_DIR:/app --privileged --name clair-singularity --link clair:clair clair_singularity pytest tests/ --cov clair_singularity --cov-report term-missing
   - coveralls