CLUST REC NOT FOUND FOR SEC IDX REC

  rb://1230 Approved by Marko

  This is basically address an issue that rows are skipped for primary
  index, but built into secondary index during online table rebuild.
  As bug described, row_merge_skip_rec() is called for primary index,
  but secondary index is still built. So the simple fix is to remove
  such row_merge_skip_rec() check when we insert row to index, so that
  they can be dropped altogether by online log application.

  However, the row_merge_skip_rec() is added mainly to address the BLOB
  issue, since BLOB can be dropped for rollback operation. To deal with
  it,we will need to log enough prefix so that any prefix index on blob
  data can be built even if the BLOB is dropped.

  In this implementation, we logged the row_ext_t for any such rows
  during its rollback drop, of course, only for dynamic and compressed
  table. And we will reconstruct a valid row_ext_t when we actually
  delete the entry in primary index as well as in secondary index.