config_file.c: Fix error handling
config_file.c: Fix error handling

set res to FALSE in case of an error if there is no function that could
set res itself. Otherwise the return value of the surrounding function
will not match the detected error.

Signed-off-by: Enrico Jorns <a2e5f936c390f36494e46e71bcfbe365bb1e8c49@pengutronix.de>

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