bash: Fix-for-CVE-2014-6278

This vulnerability exists because of an incomplete fix for CVE-2014-6271, CVE-2014-7169, and CVE-2014-6277

See: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6278



(From OE-Core daisy rev: de596b5f)

Signed-off-by: Catalin Popeanga <Catalin.Popeanga@enea.com>
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>