In SGSN, actually place the port in the SGSN config by default, so that the
gsup port may now be omitted in the VTY config (the IP address suffices).
Adjust the osmo-sgsn.cfg example.
Depends: I4222e21686c823985be8ff1f16b1182be8ad6175 (libosmocore)
Change-Id: I50f2040e2eb0baacb43849e93cfed10cbc2fc156