Coverity warns (CID 1390634) that open_net_route() is not
checking the return value from sscanf(), which means that
it might then use values that aren't initialized.

Errors here should in general not happen since we're passing
an assumed-good /proc/net/route from the host kernel, but
if we do fail to parse a line then just skip it in the output
we pass to the guest.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20190205174207.9278-1-peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>