bash: sync up with latest version in Gentoo

This fixes another piece of the mess but the story isn't over yet.

http://www.openwall.com/lists/oss-security/2014/09/25/10
https://bugs.gentoo.org/show_bug.cgi?id=523592
Merge pull request #877 from marineam/bash

bash: sync up with latest version in Gentoo