bugfix imgtool verify()
bugfix imgtool verify()

Signed-off-by: Christian Skubich <2314b2e3a4a1f7db165be2aafbf1efd78f28cc97@skubware.de>

runtimeco/mcuboot,utzig/mcuboot,ATmobica/mcuboot,runtimeco/mcuboot,ATmobica/mcuboot,ATmobica/mcuboot,utzig/mcuboot,utzig/mcuboot,ATmobica/mcuboot,tamban01/mcuboot,utzig/mcuboot,tamban01/mcuboot,tamban01/mcuboot,runtimeco/mcuboot,runtimeco/mcuboot,runtimeco/mcuboot,tamban01/mcuboot,tamban01/mcuboot,ATmobica/mcuboot,utzig/mcuboot