linux-user: Fix SO_ERROR return code of getsockopt()

linux-user: Fix SO_ERROR return code of getsockopt()

Add translation for the host error return code of:
    getsockopt(19, SOL_SOCKET, SO_ERROR, [ECONNREFUSED], [4]) = 0

This fixes the testsuite of the cockpit debian package with a
hppa-linux guest on a x86-64 host.

Signed-off-by: Helge Deller <deller@gmx.de>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <Y9QzNzXg0hrzHQeo@p100>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>