Revisit criterion for number of clicks to perform first backup

[kristovatlas]

OBPPV3-CR61 is:

Number of clicks to create the first wallet backup

This is currently only used as a criterion for OBPPV3-CM56:

Use eternal backups

Under this attack:

Users may reuse non-ECDH addresses due to the fear of losing funds if avoiding reuse increases the risk that wallet backups will become unexpectedly invalid

The other criterion under that countermeasure is OBPPV3-CR62:

Number of clicks needed to update an existing backup due to the creation of a new receiving or change address

CR61 doesn’t seem relevant to the privacy properties of eternal backups; you’re equally screwed whether you reuse addresses or not if you do 0 backups. CR62 does properly capture the intention of the countermeasure, IMHO.

If others agree, we can simply delete this criterion.

[dcousens]

Happy to delete

[crwatkins]

Good to delete.