openggsn: Update and install systemd service file

This might require to rebuild the freshly built openggsn to
fix the libgtp0 depedency. I had this issue on Dora without
a PRServer. I am not sure it applies to edison or other configs.

Bump the PR of OpenBSC to force a rebuild of the SGSN.

Fixes: SYS#176
2 files changed