when calling libusb_exit() clear usb_ctx and libusb_inited
when calling libusb_exit() clear usb_ctx and libusb_inited

dmitriykuptsov/yubikey-personalization,dmitriykuptsov/yubikey-personalization,eworm-de/yubikey-personalization,eworm-de/yubikey-personalization,Yubico/yubikey-personalization,dmitriykuptsov/yubikey-personalization,Yubico/yubikey-personalization-dpkg,Yubico/yubikey-personalization,eworm-de/yubikey-personalization,Yubico/yubikey-personalization-dpkg,Yubico/yubikey-personalization-dpkg