add execution of manage_submodule.py in travis.yml
add execution of manage_submodule.py in travis.yml

uclouvain/OSIS-Louvain,uclouvain/osis,uclouvain/OSIS-Louvain,uclouvain/OSIS-Louvain,uclouvain/osis,uclouvain/osis,uclouvain/osis