Revert "[db] Keep track of the current gsm_network"

This was a stupid decision. We will have to assign the
network at some other place. The problem will be a problem
when we have two gsm_networks in one process and the same
subscriber is traveling in both networks.
diff --git a/src/bsc_hack.c b/src/bsc_hack.c
index c80ffd5..188ccf6 100644
--- a/src/bsc_hack.c
+++ b/src/bsc_hack.c
@@ -970,7 +970,7 @@
 	bts = &gsmnet->bts[0];
 	bootstrap_bts(bts);
 
-	if (db_init(database_name, gsmnet)) {
+	if (db_init(database_name)) {
 		printf("DB: Failed to init database. Please check the option settings.\n");
 		return -1;
 	}