NOTICE: This commit implies an API change when using libosmogsm.
However, the previous API was never available in any libosmogsm release,
and only available in both libosmogsm and osmo-hnodeb master, so we are
only breaking compatibility between different master versions, which is
acceptable.
Related: SYS#5969
Change-Id: Ia26a945147d68511bb1750d51ed91909e48b4139