openposix/.../sigaction/templates/{18,19,28}

The sig_atomic_t does not imply volatile.

This fixes the testcases when compiled with -O2.

Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
openposix/.../sigaction/{18,19,28}: Regenerate.

Signed-off-by: Cyril Hrubis <chrubis@suse.cz>