[build] Add missing flag.

Author: Breakthrough

.travis.yml

@@ -47,19 +47,18 @@ install:
 
 script:
   - python -m pytest tests/
-  # TODO: Install and test the built Python packages.
   # TODO: Install ffmpeg/mkvtoolnix to run split-video tests.
 
   # Install and test source distribution.
   - python -m pip install dist/scenedetect-`python -c "import scenedetect; print(scenedetect.__version__[1:])"`.tar.gz
   - scenedetect version
   - scenedetect -i tests/resources/testvideo.mp4 -b opencv detect-content time -e 2s
   - scenedetect -i tests/resources/testvideo.mp4 -b pyav detect-content time -e 2s
-  - python -m pip uninstall scenedetect
+  - python -m pip uninstall -y scenedetect
 
   # Install and test binary wheel.
   - python -m pip install dist/scenedetect-`python -c "import scenedetect; print(scenedetect.__version__[1:])"`-py3-none-any.whl
   - scenedetect version
   - scenedetect -i tests/resources/testvideo.mp4 -b opencv detect-content time -e 2s
   - scenedetect -i tests/resources/testvideo.mp4 -b pyav detect-content time -e 2s
-  - python -m pip uninstall scenedetect
+  - python -m pip uninstall -y scenedetect