main/libusb: renamed from libusbx

upstream libusbx has merged back to libusb
http://libusbx.org/
main/libdc1394: rebuild with libusb
main/libfprint: rebuild with libusb
main/libgphoto2: rebuild with libusb
main/libusb-compat: rebuild with libusb
main/openobex: rebuild with libusb
main/oscam: rebuild with libusb
main/qemu: rebuild with libusb
main/spice-gtk: rebuild with libusb
main/upower: rebuild with libusb
main/usbredir: rebuild with libusb
main/usbutils: rebuild with libusb
testing/guvcview: rebuild with libusb
testing/hplip: rebuild with libusb
testing/libgusb: rebuild with libusb
testing/madwimax: rebuild with libusb