Refer to scheduler via hydra and not charon.

src/libcharon/plugins/kernel_netlink/kernel_netlink_net.c

@@ -241,7 +241,7 @@ static void fire_roam_job(private_kernel_netlink_net_t *this, bool address)
 			now.tv_usec -= 1000000;
 		}
 		this->last_roam = now;
-		charon->scheduler->schedule_job_ms(charon->scheduler,
+		hydra->scheduler->schedule_job_ms(hydra->scheduler,
 				(job_t*)roam_job_create(address), ROAM_DELAY);
 	}
 }