Add simple supervisor recipe.

This commit includes a testing cookbook that patches the opscode
supervisor cookbook since it does not install the daemon control scripts
on RHEL-based systems.
recipes/server: Set devpi home directory.
recipes/server: Create server data directory.
recipes/supervisor: Add devpi-server job.
recipes/supervisor: Add server_port attribute.
Merge branch 'feature/daemonize-with-supervisor' into develop