ssh-publickey-acceptance.nse: Single failure of script removes all successses

[MegaManSec]

The ssh-publickey-acceptance.nse script has a bug related to how it saves successful keys.

Imagine you have: 1 host, 1 user, and 3 keys.
When scanning with ssh-publickey-acceptance.nse, if the first key is accepted but the second or third attempt results in a failure in the script (e.g. if nmap cannot connect to the server anymore), the accepted key is not saved and reported to the user.

It should report the success, despite later failures.