cpg: Use list_del instead of qb_list_del

Just cherry picking was not enough for backporting
"cpg: Handle fragmented message sending interrupt"
(aa62c2c0286ea3e3429541fa7132513db905daa9) commit.

Signed-off-by: Jan Friesse <jfriesse@redhat.com>

lib/cpg.c

@@ -498,7 +498,7 @@ cs_error_t cpg_dispatch (
 					 * been reported to sending client. Therefore here last assembly will be dropped.
 					 */
 					if (assembly_data) {
-						qb_list_del (&assembly_data->list);
+						list_del (&assembly_data->list);
 						free(assembly_data->assembly_buf);
 						free(assembly_data);
 						assembly_data = NULL;