setup.py fails with [Errno 2] No such file or directory maintenance/napps/__init__.py

[italovalcy]

When you install maintenance using python setup.py develop, it fails with the following error:

Finished processing dependencies for kytos-maintenance==0.1
error: [Errno 2] No such file or directory: 'maintenance/napps/__init__.py'

Steps to reproduce:

docker run --privileged --name test -d kytos/nightly tail -f /dev/null
docker exec -it test bash
for napp in storehouse of_core flow_manager topology of_lldp pathfinder mef_eline maintenance; do git clone https://github.com/kytos/$napp;  cd $napp; python3 setup.py develop; cd ..; done

I think the error is the same as in other napps - see https://github.com/kytos/mef_eline/issues/191