expect: don't run aclocal in do_configure

expect: don't run aclocal in do_configure

expect has a hand-maintained aclocal.m4 so don't run aclocal, which has the
side effect of not deleting the aclocal.m4 file which pulls in macros.

The build works without this change more through luck and a combination
of behaviours than design.

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Steve Sakoman <steve@sakoman.com>