Fix the libusb detection script.
Fix the libusb detection script.

Signed-off-by: Marcus Meissner <247731c75f3b277594afe05f8b1d0ee049da0b08@jet.franken.de>
Signed-off-by: Linus Walleij <67b0e6e4a7f8300bccd309fb10a9106ef3d7b5b0@df.lth.se>

pierrezurek/libmtp,kbhomes/libmtp-zune,reverendhomer/libmtp,vmandela/libmtp,olunx/libmtp,libmtp/libmtp,jemc/libmtp,reverendhomer/libmtp,libmtp/libmtp,Bluerise/libmtp,olunx/libmtp,mmalecki/libmtp,jemc/libmtp,pierrezurek/libmtp,philipl/libmtp,libmtp/libmtp,reverendhomer/libmtp,mmalecki/libmtp,kbhomes/libmtp-zune,reverendhomer/libmtp,vmandela/libmtp,jemc/libmtp,philipl/libmtp,philipl/libmtp,mmalecki/libmtp,Bluerise/libmtp,Bluerise/libmtp,jemc/libmtp,olunx/libmtp