[WEBSITE] 4.7.2 only has sha512 file not sha1 file
[WEBSITE] 4.7.2 only has sha512 file not sha1 file

Descriptions of the changes in this PR:

*Motivation*

Since 4.7.2 bookkeeper releases only provide sha512 file, not sha1 file.

Author: Sijie Guo <sijie@apache.org>

Reviewers: Matteo Merli <mmerli@apache.org>

This closes #1647 from sijie/update_website_472

sijie/bookkeeper,sijie/bookkeeper,sijie/bookkeeper,apache/bookkeeper,apache/bookkeeper,apache/bookkeeper,apache/bookkeeper,apache/bookkeeper,sijie/bookkeeper,sijie/bookkeeper,sijie/bookkeeper,sijie/bookkeeper,sijie/bookkeeper,apache/bookkeeper