4047 panic from dbuf_free_range() from dmu_free_object() while doing zfs receive
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>

*** 894,904 ****
                          uint64_t prev_snap_txg =
                              dmu_objset_ds(os)->ds_phys->ds_prev_snap_txg;
                          for (uint64_t obj = 0; error == 0;
                              error = dmu_object_next(os, &obj, FALSE,
                              prev_snap_txg))
!                                 (void) dmu_free_object(os, obj);
                          /* sync out all frees */
                          txg_wait_synced(dmu_objset_pool(os), 0);
                          dmu_objset_disown(os, FTAG);
                  }
          }
--- 894,904 ----
                          uint64_t prev_snap_txg =
                              dmu_objset_ds(os)->ds_phys->ds_prev_snap_txg;
                          for (uint64_t obj = 0; error == 0;
                              error = dmu_object_next(os, &obj, FALSE,
                              prev_snap_txg))
!                                 (void) dmu_free_long_object(os, obj);
                          /* sync out all frees */
                          txg_wait_synced(dmu_objset_pool(os), 0);
                          dmu_objset_disown(os, FTAG);
                  }
          }