Updated bash.exe/sh.exe to 3.1.20(4)

Bring bash from patchlevel 0 to patchlevel 20.

This update fixes the following security bugs:
- CVE-2014-6271
- CVE-2014-7169
- CVE-2014-7186
- CVE-2014-7187

Signed-off-by: Thomas Braun <thomas.braun@byte-physics.de>