[Toybox] Sorry for the id -u segfault.

[Rob Landley]

Just checked in a fix.

When I switched to using the adjusted option string (to make patch -d
and --dry-run work as described in detail at
http://landley.net/notes-2016.html#23-06-2016) this meant there were ^A
placeholders being converted to NUL (so you can't trigger them even if
you did do -^A options on the command line), but the [group] logic was
still looking for ^A and if it didn't find it would fall off the end.

That's why id -u wasn't working when security blanket type was "none",
that disabled the -Z option which was in an option group.

Sorry 'bout that,

Rob