[gentoo-hardened] New sudo format string vuln

[RB]

Not sure how much testing anyone else has done (and it warrants more
testing), but I just tested this on a rather out-of-date machine
running hardened-sources-3.0.4 and sudo-1.8.2-r1.  I had brute-force
prevention enabled, and not only was the vulnerability not successful,
I was locked out from all execution under my UID for 15 minutes -
couldn't even su over from root.  Definite win for hardened!