glibc/eglibc: Clean up package warnings and potentially broken data in -dev package

glibc/eglibc: Clean up package warnings and potentially broken data in -dev package

These changes ensure files packaged in the -locale package aren't included
in the main do_install and also ensures the staging directory used for
the -locale package doesn't end up in the -dev package.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>