more explicit assertion failure

src/core/disk.c

@@ -75,7 +75,7 @@ int starpu_disk_register(struct starpu_disk_ops *func, void *parameter, starpu_s
 	char name[16];
 	snprintf(name, sizeof(name), "DISK%d", n);
 	msg_host_t host = _starpu_simgrid_get_host_by_name(name);
-	STARPU_ASSERT(host);
+	STARPU_ASSERT_MSG(host, "Could not find disk %s in platform file", name);
 	_starpu_simgrid_memory_node_set_host(memory_node, host);
 #endif