Fix #484: JOIN doesn't save data to snapshot

1. snapshot_save calls snapshot_space
2. snapshot_space uses index->initIterator()
3. initIterator() doesn't work until endBuild() is called
4. index->endBuild() is called by space_end_recover_snapshot()
   *after* snapshot_save()
=> Replica doesn't save some tuples into snapshot on JOIN

This patch changes space_end_recover_snapshot() order.