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/db.c b/src/db.c
index f2f691e..4abd636 100644
--- a/src/db.c
+++ b/src/db.c
@@ -32,7 +32,6 @@
 static char *db_basename = NULL;
 static char *db_dirname = NULL;
 static dbi_conn conn;
-static struct gsm_network *current_network = NULL;
 
 static char *create_stmts[] = {
 	"CREATE TABLE IF NOT EXISTS Meta ("
@@ -94,7 +93,7 @@
 	printf("DBI: %s\n", msg);
 }
 
-int db_init(const char *name, struct gsm_network *network) {
+int db_init(const char *name) {
 	dbi_initialize(NULL);
 	conn = dbi_conn_new("sqlite3");
 	if (conn==NULL) {
@@ -125,7 +124,6 @@
 		return 1;
 	}
 
-	current_network = network;
 	return 0;
 }