vty: fix segfault if rf_ctl is not set
This is the case of osmo-nitb, since it does not call
osmo_bsc_rf_create().
term1: $ ./osmo-nitb -c ../openbsc.cfg.nanobts
term2: $ telnet localhost 4242
term2: OpenBSC> show network
term1: Segmentation fault
diff --git a/openbsc/src/libbsc/bsc_vty.c b/openbsc/src/libbsc/bsc_vty.c
index c0909db..1afaed3 100644
--- a/openbsc/src/libbsc/bsc_vty.c
+++ b/openbsc/src/libbsc/bsc_vty.c
@@ -189,7 +189,7 @@
dump_pchan_load_vty(vty, " ", &pl);
/* show rf */
- if (net->msc_data)
+ if (net->msc_data && net->msc_data->rf_ctl)
vty_out(vty, " Last RF Command: %s%s",
net->msc_data->rf_ctl->last_state_command,
VTY_NEWLINE);