pg_resetwal: Update an obsolete comment
The comment claimed that pg_resetwal updates the pg_control file if it
is of an old version. This has apparently never been true. Also, in
c3c09be34b, another comment was added elsewhere that this currently
does not happen. So this comment is wrong and redundant and can be
removed.
Reviewed-by: Aleksander Alekseev <aleksander@timescale.com>
Discussion: https://www.postgresql.org/message-id/flat/
0f3ab4a1-ae80-56e8-3426-
6b4a02507687@eisentraut.org