test/rauc.t: add test for rauc info with explicit config
test/rauc.t: add test for rauc info with explicit config

In this case, the verification information comes from the config file instead
of from the commandline.

Signed-off-by: Jan Luebbe <3a82f1ac4ad59607a20f180f1c67ac8ba31ad0d5@pengutronix.de>

rauc/rauc,jluebbe/rauc,rauc/rauc,ejoerns/rauc,jluebbe/rauc,jluebbe/rauc,ejoerns/rauc,rauc/rauc,ejoerns/rauc