scripts: fix catching failures

POSIX 1003.1-2008 does not say whether "set -e" should catch a sub-shell
that exits with !0 (it has a list of conditions to catch, but no list of
conditions not to catch, and this situation is not listed).

bash-3 does not catch such a failure, but bash-4 does. That why, on my
Squeeze system I did not see the issue, while Thomas did on is Lenny chroot.

Reported-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

 # ARM specific configuration file

 ## select ARCH_SUPPORTS_32

 ## select ARCH_DEFAULT_32

 ## select ARCH_SUPPORTS_BOTH_MMU

 ## select ARCH_DEFAULT_HAS_MMU

 ## select ARCH_SUPPORTS_BOTH_ENDIAN

 ## select ARCH_DEFAULT_LE

 ## select ARCH_SUPPORTS_WITH_ARCH

 ## select ARCH_SUPPORTS_WITH_CPU

 ## select ARCH_SUPPORTS_WITH_TUNE

 ## select ARCH_SUPPORTS_WITH_FLOAT

 ## select ARCH_SUPPORTS_WITH_FPU

 ## select ARCH_SUPPORTS_SOFTFP

 ##

 ## help The ARM architecture, as defined by:

 ## help     http://www.arm.com/