ovn-northd: add chassis nonull check
op->sb->gateway_chassis[0]->chassis may null in some special cases, need
to add a check to avoid segment fault.
@@ -1887,6 +1887,7 @@ ovn_port_update_sbrec(struct northd_context *ctx,
/* If we found the chassis, and the gw chassis on record
* differs from what we expect go ahead and update */
if (op->sb->n_gateway_chassis != 1
+ || !op->sb->gateway_chassis[0]->chassis
|| strcmp(op->sb->gateway_chassis[0]->chassis->name,
chassis->name)
|| op->sb->gateway_chassis[0]->priority != 0) {
