Unnecessary smgropen in {heapam_relation,index}_copy_data?

Hi, hackers

I find heapam_relation_copy_data() and index_copy_data() have the following code:

    dstrel = smgropen(*newrlocator, rel->rd_backend);

    ...

    RelationCreateStorage(*newrlocator, rel->rd_rel->relpersistence, true);

The smgropen() is also called by RelationCreateStorage(), why should we call
smgropen() explicitly here?

I try to remove the smgropen(), and all tests passed.