changes:
- remove some unnecessary logics derived from libusb-0.1
- now PROVIDES libusb
- bluez4 depends on libusb instead of libusb-compat
libusb-0.1 vs. libusb-compat
libusb-compat is intended to be a drop-in replacement of libusb-0.1,
building on top of libusb-1.0 (which has different API from -0.1).
Few known packages don't work with libusb-compat, notable example
is libmtp. Since most packages work very well with libusb-compat,
and libusb-compat doesn't suffer from power consumption issue of
libusb-0.1 (which is often very important for embedded systems),
drop libusb-0.1 and move to libusb-compat completely. If we see
any problems in the future, either the package should be fixed
or we can add back libusb-0.1 as needed.
