The key referred to in `modules/rhizo_base/manifests/openbsc.pp`. A
default value of 0 (anything but "1") will result in a new config
being generated from a template.
rhizo::grps is referred to in
`modules/rhizo_base/manifests/init.pp`. The default value of "none" is
only a guess but allows puppet provisioning to complete and the
osmocom stack to start.
The ntp_servers key is referred to in
`modules/rhizo_base/manifests/init.pp` and was otherwise undefined. It
is in the common file since it seems similar to other parameters
already in the file, but there is no strict reason for the current
location. The assigned value is also just an initial default guess.