7127  remove -Wno-missing-braces from Makefile.uts

*** 708,718 ****
          dmu_replay_record_t *drr;
          dmu_sendarg_t *dsp;
          int err;
          uint64_t fromtxg = 0;
          uint64_t featureflags = 0;
!         struct send_thread_arg to_arg = { 0 };
  
          err = dmu_objset_from_ds(to_ds, &os);
          if (err != 0) {
                  dsl_pool_rele(dp, tag);
                  return (err);
--- 708,718 ----
          dmu_replay_record_t *drr;
          dmu_sendarg_t *dsp;
          int err;
          uint64_t fromtxg = 0;
          uint64_t featureflags = 0;
!         struct send_thread_arg to_arg = { .error_code = 0 };
  
          err = dmu_objset_from_ds(to_ds, &os);
          if (err != 0) {
                  dsl_pool_rele(dp, tag);
                  return (err);