Revert "bash: Fix CVE-2019-18276"

This reverts commit 09e69524.

This isn't a Backport as indicated in patch and not all the changes in
this change are relevant to the CVE. Revert and wait for the fix
to be available upstream.

(From OE-Core rev: f39285bb82e68945a81034b84da09ca1078d6719)

Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>