* util/grub-mkconfig.in: Use 'set -e' rather than '#! /bin/sh -e',

* util/grub-mkconfig.in: Use 'set -e' rather than '#! /bin/sh -e',
to avoid accidents when debugging with 'sh -x'.
* util/grub-mkrescue.in: Likewise.
* util/grub.d/00_header.in: Likewise.
* util/grub.d/10_hurd.in: Likewise.
* util/grub.d/10_kfreebsd.in: Likewise.
* util/grub.d/10_linux.in: Likewise.
* util/grub.d/10_netbsd.in: Likewise.
* util/grub.d/10_windows.in: Likewise.
* util/grub.d/20_linux_xen.in: Likewise.
* util/grub.d/30_os-prober.in: Likewise.
* util/powerpc/ieee1275/grub-mkrescue.in: Likewise.