gsm48: Use NULL instead of 0 for pointers in C.
diff --git a/openbsc/src/gsm_04_08.c b/openbsc/src/gsm_04_08.c
index 810115f..521dab4 100644
--- a/openbsc/src/gsm_04_08.c
+++ b/openbsc/src/gsm_04_08.c
@@ -241,7 +241,7 @@
 
 	bsc_del_timer(&conn->loc_operation->updating_timer);
 	talloc_free(conn->loc_operation);
-	conn->loc_operation = 0;
+	conn->loc_operation = NULL;
 	msc_release_connection(conn);
 }