[pkg-gnupg-maint] GnuPG 2.1.12 requires libusb-1.0-0-dev for scdaemon

[NIIBE Yutaka]

Hello,

GnuPG 2.1.12 migrated to newer libusb.  For Debian Build-Depends, we
should replace libusb-dev (which refers old libusb) to
libusb-1.0-0-dev, so that scdaemon will be built with newer libusb.

Currently (in experimental), scdaemon is built with no libusb support.
It works only when PC/SC is available on a system.  (scdaemon
dynamically loads the pcsc library if available.)
--