scripts/bootstrap.sh: Allow CONFIG_PROTECT

scripts/bootstrap.sh: Allow CONFIG_PROTECT

With a CONFIG_PROTECT="-*" setting, glibc will overwrite the system's
/etc/locale.gen file in src_install() with its default-empty one. In
pkg_postinst() it reads the empty /etc/locale.gen it just installed, and
as a result generates all locales.

So, allow CONFIG_PROTECT to be passed through unmolested so long as it
starts with "-*". This allows locales to be selectively enabled when
bootstrap.sh is run with CONFIG_PROTECT="-* /etc/locale.gen".

Signed-off-by: Matt Turner <mattst88@gentoo.org>