libusb:
 * rename FREETZ_LIB_libusb symbol to FREETZ_LIB_libusb_0
 * fixes libusb-install pattern matches both libusb-0.1 and libusb-1.0 causing (under some circumstances) both libusb-0.1 and libusb-1.0 to be installed even though only libusb-0.1 is required
 * refs #2072


git-svn-id: file:///var/svn/freetz/trunk@10867 149334a1-2f27-0410-a3b9-fc62619ac1e6