Increase how long supervisor waits for workers to stop.

This is set as 5 days for now because we have seen "grade_course" tasks that
take about 4 days to complete for large classes and if we shutdown before
they are done we end up in a bad state in the database.
Merge pull request #1410 from edx/feanil/increase_worker_timeout

Increase how long supervisor waits for workers to stop.
We have to keep upstart from killing supervisor.

Supervisor could wait up to 5 days for workers to finish jobs. So
Upstart needs to wait that long for supervisor to finish.
Merge pull request #1412 from edx/feanil/increase_worker_timeout

We have to keep upstart from killing supervisor.
Configure hosts for Studio Preview button in devstack and jenkins
using ansible_hostname as COMMON_HOSTNAME for devstack
add check for COMMON_HOSTNAME length