ttcn3-ggsn-test-ogs: set CAP_NET_RAW for open5gs-upfd
The SO_BINDTODEVICE feature (used for VRF) requires CAP_NET_RAW. Since we run open5gs-upfd as user "osmocom", that seems to be causing some permission problems under some systems (like jenkins). Let's make sure we add the capabilitites to the binary before launching it as user "osmocom".
