split bsc_bootstrap_network() in alloc and config

For patch clarity, keep some code dup to be removed in a subsequent patch. In
the same sense don't change the fact that mncc_sock_init()'s return value is
ignored.

The global gsm_network instance 'bsc_gsmnet' is basically only used by the VTY,
and a future patch will "hide" that global in a vty .c file. In a nutshell, I
want to

- first allocate a gsm_network,
- then initialize the VTY passing the gsm_network pointer,
- and then read the config file using the initialized VTY.

So far, bsc_bootstrap_network() allocates the gsm_network and reads the config
file right away, which only works by sharing the extern bsc_gsmnet pointer,
which I would like to uncouple.

Change-Id: I480a09a31a79766ad07b627dd5238b7e37f3be7a
diff --git a/openbsc/src/libbsc/bsc_init.c b/openbsc/src/libbsc/bsc_init.c
index 917dd73..9e913d6 100644
--- a/openbsc/src/libbsc/bsc_init.c
+++ b/openbsc/src/libbsc/bsc_init.c
@@ -476,12 +476,8 @@
 	return 0;
 }
 
-int bsc_bootstrap_network(mncc_recv_cb_t mncc_recv, const char *config_file)
+int bsc_network_alloc(mncc_recv_cb_t mncc_recv)
 {
-	struct gsm_bts *bts;
-	int rc;
-
-	/* initialize our data structures */
 	bsc_gsmnet = bsc_network_init(tall_bsc_ctx, 1, 1, mncc_recv);
 	if (!bsc_gsmnet)
 		return -ENOMEM;
@@ -489,6 +485,14 @@
 	bsc_gsmnet->name_long = talloc_strdup(bsc_gsmnet, "OpenBSC");
 	bsc_gsmnet->name_short = talloc_strdup(bsc_gsmnet, "OpenBSC");
 
+	return 0;
+}
+
+int bsc_network_configure(const char *config_file)
+{
+	struct gsm_bts *bts;
+	int rc;
+
 	rc = vty_read_config_file(config_file, NULL);
 	if (rc < 0) {
 		LOGP(DNM, LOGL_FATAL, "Failed to parse the config file: '%s'\n", config_file);