sgsn: Fix the unimplemented/uninstalled show ggsn command

This is fixing a GCC and Coverity warning.

GCC:
sgsn_vty.c: At top level:
sgsn_vty.c:308:1: warning: ‘show_ggsn_cmd’ defined but not used [-Wunused-variable]

Coverity: CID 1040727
1 file changed
tree: 24f770ed13407c7febbbe50720a6f0c9e23c42ee
  1. debian/
  2. hlrsync/
  3. linux-kernel/
  4. openbsc/
  5. wireshark/
  6. README