ash backticks busted in 1.2.2.1

[Bennett Todd]

At least I'm assuming that the "sh" cmd in busybox is ash when ash
is enabled. I did a busybox build on Red Hat Enterprise Linux 4,
statically linking against glibc, with everything in busybox turned
on; in the result backticks don't work. E.g.

	echo `ls`

prints nothing.

If you have trouble reproducing this let me know, I can provide the
.config, gcc and libc details, etc.

-Bennett