The function removes a sequence object created before by sequence_set or sequence_next.
The function returns integer one if the sequence object is removed, zero if there was no object with the specified name.
This sequence of operations demonstrates how sequence_remove reverts the effect of sequence_next.
> select sequence_next ('my_sequence');
0
> select sequence_next ('my_sequence');
1
> select sequence_next ('my_sequence');
2
> select sequence_remove ('my_sequence');
1
> select sequence_next ('my_sequence');
0