Don't copy makepkg.conf into the chroot

Replacing the chroot's makepkg.conf with our own prevents us
from building i686 packages in a i686 chroot on a x86_64 host.

[Aaron: Plus additional whitespace edits]

Signed-off-by: Evangelos Foutras <foutrelis@gmail.com>
Signed-off-by: Aaron Griffin <aaronmgriffin@gmail.com>