migrate to oap_client in libosmogsm

libosmogsm in libosmocore.git from Change-Id
Ie36729996abd30b84d1c30a09f62ebc6a9794950 onwards contains oap_client.c,
so we don't need our local copy here in this repo anymore.

Change-Id: Ib6496c35d0ce6eb531e97129dc45a9f68e503b34
Requires: libosmocore.git Change-Id Ie36729996abd30b84d1c30a09f62ebc6a9794950
7 files changed