Spambot does not actually block accounts

Problem/Motivation

When spambot scans accounts on cron and tries to block the account, the account doesn't actually get blocked, even when this message appears in watchdog: "Blocked spam account: @name <@email> (uid @uid)'".

Steps to reproduce

Run cron with a spam account on the site. Observe it is not blocked.

Proposed resolution

I think this is because `$account->save()` is not called after `$account->block()` in spambot_cron().