Add python-sphinx in trusty to ubuntu-trusty; resolves travis-ci/apt-package-whitelist#4109
Add python-sphinx in trusty to ubuntu-trusty; resolves travis-ci/apt-package-whitelist#4109

Packages: python-sphinx python3-sphinx sphinx-common sphinx-doc libjs-sphinxdoc

travis-ci/apt-package-whitelist,travis-ci/apt-package-whitelist