linux-user/signal.c: Don't pass sigaction uninitialised sa_flags When forcing a fatal signal, we weren't initialising the sa_flags field in the struct sigaction we used to reset the signal handler to SIG_DFL. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>