mgmt: use prod environment in module run config

Fixes #114.

When building OSv image we should use set of paths from 'prod' config.

This was introduced in commit c29222c6bc09015c22a1b85979297d4387bdab75
and then copied to module.py.

Signed-off-by: Tomasz Grabiec <tgrabiec@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>